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Hello! This is my first post on stargazer’s lounge, so forgive me if this is the wrong place to ask. I have a SkyWatcher AZ-GTi mount (with a firmware update + eq wedge so that it can run in eq mode). I also have a Raspberry Pi 4 with INDI, KStars, and Ekos tools. I don’t have a guidescope (and my budget is extremely limited), so I was wondering if there was a way to polar align my DSLR using just the software running on the Raspberry Pi. I’m also competent in Python, if that could be useful for anything.

Hi all, as a complete beginner, who is gradually getting some kit together, the question of which Polar Alignment App I should get for my Android phone is exercising my mind. Looking at the android play store there seems to be a myriad to choose from, which do members recommend & why?

Hi All When I use SynscanInit to help me to Polar Align, it shows me an image of Polaris against an Octans reticle (as fitted in my Polar Alignment Scope) as follows: However, when I look through my Polar Alignment Scope, the image I see is like this: It's upside down with respect to the SynscanInit view. So my questions are: 1. Is my Polar Alignment Scope fitted upside down in my mount (SW EQ3-Pro)? 2. If not, How do I read the information from SynscanInit? Should I position Polaris in the corresponding position, ie at the top of my view? Thanks in advance Mark P.S. Sorry for the huge pictures.

Okay, I'll try to make this as short as possible. Info: I have a EQ5 mount (soon to become motorised and GOTO'd) and, after reading countless astrophotographers praise the QHY PoleMaster, I thought it'd be a good idea to follow in their footsteps and buy myself a PoleMaster. I saw nothing about the PoleMaster supporting the EQ5, so I thought I'd ask whether or not the PoleMaster would make my life easier by supporting the EQ5. Clear skies, Leon.

So i just got my first telescope as a gift for my birthday which is celestron powerseeker 114EQ, and what i want to ask is do i have to do the polar alignment before i use it and what is the purpose of polar alignment?

Hello fellow astronomers! I'm an amateur astrophotographer and a student and I made a Polar Alignment app for Android for German equatorial mounts. I kept the UI very simple and easy to use. If you would like to share some feedback, that would be very helpful. Cheers and clear skies!

Hi, Please please please need some help on my NEQ6, its more about polar alignment on goto EQ mounts in general probably. Please allow me to list all the things I have done because l really want to know if I have done anything wrong during my polar alignment....as my goto can't find anything . It was last night 14th oct, my first time ever with clear sky with my first ever outdoor dressed rehearsal with my NEQ6 purchased circa 4 was ago so I did the polar alignment, i.e. I levels the whole mount first (i.e. Using a spirit leveller to make sure I have the home position of the mount 99.999% correct), found Polaris somewhere in my polar scope, centred it on my reticule cross hair, used the NEQ6's altitude (so I am only adjusting the mount vertically) nob to move Polaris on to its orbit (printed in the polar scope sight) around NCP, rotated the polar scope around its RA so the Polaris circle has Polaris inside. Rotated the polar scope again so the RA clock on the mount reads polaris's last transit (a read out from my NEQ6 handset's Hour Angle reading, verified with my polar align iOS app), and finally using both my Alt & Az bolts to again place Polaris within the Polaris circle printed out in the polar scope sight. By the way, I did all of this while the mount is switched on, mainly because I need the polar scope to have the LED on, and the handset to tell me the HA of Polaris anything wrong so far? So I at that point turned off my mount, my telescope was at a strange and awkward angle. I returned the mount to the home position by disengaging both clutches of RA and Declination (i.e. Manually returning my telescope pointing straight up). i then turned my mount back on, re-entered all the date/time/long&lat...etc, then did a 2 stars alignments , chosen my 1st star (Vega) , the mount started to slew and BOOM....., only that it ended up pointing towards something completely different.....:( i was very saddened... because that whole process took my novice self good 30-40 minutes, only to find I probably did soemthing wrong. experienced SGL'ers, help me! All I want it to take some short light frames so I can start enjoy astrophotography like your guys ?

Hello. I was hoping someone might be able to help me??? This is my first post, so first off I just want to say a big "hello" to everyone here at Stargazers Lounge. My equipment is: Skywatcher ED 80 + FF/HEQ5/V2.04 Skyscan handcontroller/Tracer 12v battery/Canon 6D, I am not guiding or using a PC. My issue is......I can't get the GOTO function to work perfectly. My HEQ5 GOTO keeps on missing its target everywhere when I do a 2 star alignment. The target is just outside the field of view using a ED80 and 28mm eyepiece. When I do a 1 star alignment I seem to get much better GOTO results but start missing targets when I move further away from the star 1 used for alignment. I have done all the basics...I have callibrated the polar scope, levelled mount, entered correct info into the controller (date in US/Co-ordinates in hrs+mins) Polar aligned ok, tightened Dec and RA bolts and made sure HEQ5 is in home position before turning on the power, tried to centre the star when aligning etc. A few things I noticed over 3 nights of using my HEQ5 were: Night 1) Tried a few two star alignments with Alkaid and Betelgeuse but i found that the Goto was off on Jupiter and the moon in the East. I could see the light of the moon through the telescope but had to the center using the handset. Same issue with Jupiter.Tried again from scratch 3 times but always the same result. I used the same alignment stars because I'm not so sure on others yet apart from the obvious and some of those were not on the list the skyscan controller gave me.I gave up on the goto in the end and just looked at Jupiter and the moon for a few hours....they were superb, I was amazed at how far I could push Jupiter with the ED80, almost better than my 200p in ways.I can see why people like refractors! Night 2)Set the mount up. Tried the same 2 stars and got the same result.However this time I tried some targets to the West in Auriga without thinking about it and the Goto seemed more accurate????Is this because I aligned with Alcaid near the North and Betelgeuse in the West, therefore it tracks better in the Western side of the Meridian? Night 3) I then tried out a 1 star alignment just to see what the difference would be (I used Alkaid) I can get M51 and M101 bang in the centre of my Canon 6D but M81/82 start to appear to the top left corner and not in the centre....the tracking seems to be going off the further I move away from my alignment star.I then chose M44 in Cancer because it is to the South and it was off in the frame to the left, like the 2 star alignment was giving me......I assumed though that maybe this is the case with one star alignment, it can cope in an area near the alignment star but as you move further away it gets worse???? Using the 1 star alignment gave me a chance to do a bit of imaging for the first time so I stuck with that. I have not tried 3 star alignment yet and I know that this helps compensate for cone error...I will be trying this next anyway to see what I get. Is there a way to get the Goto to work on targets all over the Sky? Do most imagers just choose a star near the area of sky they want to image in and use the 1 star alignment?? For visual I thought the 2 star alignment should work but to be honest the 1 star was better!! I would really like to get the GOTO to work on any target i choose wherever it is in the sky. Anyway I've just started so I have a lot to try and experiment with but I thought I would try some suggestions here because I might be missing something obvious? Any help would be fantastic Thank you and clear skies to all. PS.I have included 3 pics to show how the first 2 targets are central but the third is starting to go amiss.They are also my first ever Images so thought I would share. If anyone knows what those black marks are on my images any advice to get rid of them would be really usefull...looks like something on the sensor...or from deep outer space..lol.

I often read that leveling your mount is nonsense or a ‘myth’… Although it is not absolutely necessary to level a GEM to achieve good polar alignment, leveling is a very easy and handy way to make the first step into polar alignment, for the simple reason there is a relation between level and latitude. Latitude is always measured as a deviation from level, so why not start with level in the first place? When leveled you can use the marks on the mounts latitude adjustment scale to get a rough alignment together with azimuth adjustment. Yes, without leveling you can get polar alignment as well, but it is a lot harder, because there is nothing to start with… Especially when you cannot see Polaris at your favorite site, it is a good idea, to go to a site where you can see Polaris and prepare your mount for ‘blind’ pa, by leveling it as precise as you can, do a polar alignment as good as you can and leave the settings as they are for your next session at the ‘blind’ place. On that place point your mount roughly North with the tripod or azimuth adjuster and level again as precise as you can . Then slew to a star that you can see (preferably South) about the same latitude as Polaris. You will need to adjust azimuth to get it centered, and maybe a little tweak with latitude (because of ‘flaws’ in your bubble level), but it should be very close if you did a precise leveling... Simple one star polar alignment on a place where you cannot see Polaris! For imaging this alignment procedure together with the use of PHD will be (reasonably) ok as well.

Hi there in prepping for a dark skies expedition in November last year, I discovered that the reticule in my Vixen PAS had come away from its retainers and was rattling around in the scope. I duly got in touch with Opticron (Vixen reps in U.K.) and they were happy to repair under warranty. After a couple of weeks I received delivery of the supposedly repaired PAS, only to discover that the reticule had been placed upside down in the PAS. The PAS was then sent back to Vixen UK in December, who promised that they would fix the error and ensure that the PAS was accurately calibrated. So after waiting about 4 weeks, I received a 2nd delivery of the PAS, installed the scope in my SXW mount, and set about checking the calibration again, only to discover that the calibration was off by about 30 degrees. Communicating with the rep at Vixen UK, he apologised and said that they would replace the scope free of charge. The following day he emailed me to tell me that Vixen no longer manufactured the setting circle based PAS , it has now been replaced by the new Polar Scope P-FL and that they would send me the new product instead. Quite happy with this arrangement I waited just 48 hrs to received my new all singing all dancing P-FL. This new device utilises a 3 star alignment process to achieve polar alignment. So the old PAS was swapped out and sent back to Vixen, and the new PAS installed. Familiarising myself with the new process I found that the quality of the optics in the PAS appeared to be sadly lacking. Once focused, the image of the reticule in about the centre 1/3 of the FOV was crisp, however outside of this area the image of the reticule quickly becomes blurred. The fact the other two stars involved are at the extreme of the field of view, I can only I imagine using this in the field may prove rather frustrating as you go through the iterative process for the 3 star alignment. Apologies for the diatribe, however this whole experience has led me to wonder about the quality of goods coming out of Vixen at the moment. Does this experience match with anyone else out there? Has anyone used the P-FL in the field, are my concerns needless or am I destined for more fruitless backbreaking, neck straining experiences at my PAS? Kind Regards Paul J.

Hi, I'm new to GEM. Got a new SkyWatcher EQ5, and the enclosed reticle has me puzzled, see pic. I'm on the Northern hemisphere, but the only depicted constellation is Octans. And I'm missing the small circle to capture Polaris in. As the enclosed manual describes polar alignment with the more frequently seen reticle, as do numerous vid.s and how-tos on the web, I'm a little lost here. I suppose I have to rely on some smartphone app to tell me, where on the dial to place Polaris at a given time?! And is that reasonable? Any help greatly appreciated. Bjorn

Hello all. I've recently come across a great app - before I go any further, I have no interest in this app financially at all. As a newcomer to the hobby, I have found polar alignment quite challenging what with learning where Polaris is at any given point and how to align with a polar scope. I've got a QHY Polemaster but that doesn't let me set up in the day or at a location where Polaris isn't visible. Along comes PS Align Pro and although I'd used it for levelling the mount and the weather forecasting side of things, until today I was unaware that you can use the app to ROUGHLY polar align during the day/when Polaris isn't visible. Hopefully, this set of images and step-by-step instructions will help another newcomer like myself to get somewhere near polar alignment without a significant purchase, I think the app cost me about £3.00. On opening the app you set up your time date and location, after this you can change to various polar alignment reticules, make calculations and allsorts with this app, it is quite astounding. So, how do you align during the day? You'll need a piece of timber that is a similar width to your Dovetail/Scope mount, two short screws, a means to cut a piece of wood for a smartphone holder, a means of setting the wood square and some good old elastic bands. Step one Remove your scope from the mount and try your selected bit of timber in its place, we're using timber to 'try' and stop any metallic interference between mount and phone. Don't clamp it too tight, you may well damage or split the timber, tighten it just enough to get a good hold. Step Two Cut a 'noggin' from the end and make sure it has a square/level edge, this can be done with a simple set square etc. Step Three Insert one screw, you are better drilling a pilot hole to help you drive the screw home without splitting your 'noggin'. Step Four Align the noggin with your square and install the second screw. You should now be able to rest your phone/smart device thus Step Five Transfer the timber to your mount and attach the smart device with the super technical 'laccy bands! The image in the back is me and the Missus in Monte-Carlo BTW! Step Six, level the mount. You can use your preferred method or use the apps own level and compass bearing to roughly point you in the right way. Now, click done on the app and press the icon that looks like the sun, this will bring up the day time polar alignment module. If you're somewhere near, the app will look like this Follow the prompts (seen above as Up and R, note the arrows) and adjust your RA/DEC adjustments, the cross will start to move. Your aim is to get it looking like this or with the centre a little bit closer, I couldn't get it just right whilst screen-shotting the image! That's it!! You're somewhere near polar-aligned during the day or if Polaris isn't visible, this may not be good enough for no-trail images, but it will get you a lot closer than guesswork. Step Seven Replace scope onto the mount and you should be good to go, check your PA when it goes dark, there are other parts of this app that will help you with that too. Really hope this helps someone. Kev

Hi all, First post here, and I'm pretty new to AP, just picked up a Star Adventurer mount a couple months ago and have been happily playing around with it with DSLR and various lenses and a 72mm Sky-Watcher refractor. I'm new to the whole setup process, and I'm trying to do a decent job of leveling the tripod/mount, polar alignment, and I should probably think more about balancing the weight of things. I've gotten some decent shots, like 60-120 second subs with up to 300mm lens. My last time out I was getting star trails at 200mm and 15 second exposures, which could have been just a sloppy polar alignment, but today out of curiosity I looked through the polar scope and rotated the RA axis 360 degrees, and I saw that the target circle jumped a few times. I'm guessing that the target circle should appear not to move while the numbers 3, 6, 9, 12 would rotate around as I rotate the RA axis. So my guess is that the polar scope would need to be calibrated?

Does anyone have any tips or advice on polar aligning my Newtonian reflector and anything on aligning my right ascension setting circle? It has a RA vernier scale and this will be my first time doing all this once the weather clears up.

Near perfect polar alignment with the synscan? I doubt it, but the proof will be in the proverbial pudding. There's too much of a moon for serious imaging, but I need more training in guiding. Hope tonight there will be opportunity for that. Btw, 2-star alignment with a 2 x barlowed 17 (?) mm eyepiece with homemade reticule resulted in these numbers. The second alignment star was pretty much spot on without adjustment, so there's hope.

With EQ5 Synscan there are 90 stars embedded for polar alignment (source: http://www.vcse.hu/konyvtar/Cikkek/SkyScan_Alignment_Stars.pdf) and I was fiddling with NEQ6 the other day and it only showed me 20-odd stars. Could it be that Synscan is "hiding" the stars that are below horizon or close to it so that they don't appear or does it really have fewer stars for polar alignment?

I was wondering if anyone know the diameter of the etched reticle of the Star Adventurer polar scope I experimented a little in the past years with a diy polar scope for my barn door tracker,using this useful article: http://www.marcellocucchi.altervista.org/cannocchiale_polare.pdf Italian pdf,I or Google can traslate as needed. The polar alignment was as fast as roughly pointing in the pole area,move the "mount" up,down,left,right to center all the stars in the relative circles,done. My reticle was as this one: this is one of the best shot I got, with the barn door tracker and the custom reticle,179 s at 300mm: Significant exif data: Would this be an improvement over the SA standard reticle? I think it should allow faster polar alignment and no need to have apps or software to get the position of Polaris Comments/feedback welcome! Andrea

Sincere apologies if this has been covered previously in the numerous newbie SA questions. I had a search here and on Google using many different ways of asking but can't quite find the answer. I've just received the SA astro imaging bundle and have been familiarising myself with it before the skies clear. Am I right in assuming that by setting the date/time to October 31st at 00:00 is just to align the polar scope reticule squarely? As I understand it, once polar alignment is completed, it will rotate as the L bracket and camera are positioned. I have the PS Align app on my phone and the reticule set in that matches what I can see through the polar scope (clockwise 0, 3, 6, 9) so I think I'm on the right track and know what I'll need to do there. However, the month markings on my SA have a wider division at the end on the October range, as do all the months with 31 days. You can see them in the attached pic. The only images I've been able to find on-line (and the diagrams in the manual) show equal divisions throughout. So, I guess what I'm really asking is, do I align as per the attached photo with the 0 on the last division mark in October? The reticule looks pretty level to me but I didn't know quite how crucial it was. (I'll try not to have such a rambling question next time.) Simon.

Hey guys, following on from my last thread regarding drift alignment issues, I finally (after a year and a half of trying) managed to get what seemed to be precise polar alignment using the drift method. The goal of this is to get long(ish) unguided subs. My setup is a Skywatcher NEQ6, SW 80ED Refractor, Canon 100D DSLR and i'm using BackyardEOS to control the camera. I don't yet have a focal reducer or any form of autoguiding. Here is an image of my altitude alignment (using the D.A.R.V method), using a star at around ±10° dec from the celestial equator, as near to the east horizon as possible. (Apologies for the poor image quality - I had to use my phone camera since print screen didn't seem to want to work on the laptop). And here is my alignment for the azimuth (taken near the meridian at ~0° dec). I spent hours trying to get both as precise as possible - I think more precise alignment would have been next to impossible for me to do. Regardless, after finally feeling like i'd got good alignment, I went to take an image and I was pretty disheartened. A 30 second exposure left me with significant star trails. The longest subs I could get without trails were ~15 seconds. After nearly a year and a half of just trying to get good polar alignment, it feels like a bit of an insult, especially given that people often talk about getting 30-60 second unguided subs. But, i'm determined to eventually get there. So my question is, why is this happening? Could it be that my mount is flawed or damaged from the time I dropped it on my head? Do I just not have enough practice making the small adjustments to the mount required for unguided subs? Could balancing play into this? I've tried to balance my mount as best I can, but the dec axis is still heavily skewed towards the back/camera end of the scope and i'm unable to move the scope any further forward on the dovetail to counter this. Or could this be that i've simply hit the limit of my setup? I was always intending on buying an autoguider once I was familiar with my equipment and able to get good polar alignment, but would it be worth it? I'm a bit worried that if I can't get better alignment, an autoguider really isn't going to make much difference (and at best give me bad field rotation). Alternatively, are there any other methods of polar alignment I could use? I don't really want to use the polar scope method, and would prefer drift alignment if possible. I'm aware that pHd has a drift alignment procedure, and i'm tempted to try it if I do end up getting an auto guider. Any help or discussion is much appreciated! Cheers, Crowmium.

Night 1-first light Took me from 2100 to 2330 to set up all the software. Another Hour to setup scope, USB-2-serial, etc. No direct sight to polaris. Put up only rudimentary polar alignment (with compass), then astrotortilla for plate solving. Problem: as i had a massive polar alignment error, i was on target, but with a severe tracking error- exposures of only 5 seconds already showed star trails. Did a nice shot of M42 (orion nebula) nevertheless. (2 months break due to exceptionally bad weather) Night 2 No astrotorilla available as VM software did not start. Setup only 15 minutes, but another 45 minutes to remember how to connect camera correctly to scope (was out of focus because i had a extension in-between that was unnessessary). Setup again roughly to north with compass. Entered coordinates, date,time. Start three star alignment. 4 out of 5 suggested stars covered by house. Repeated 2 times, always the same invisible stars . Sweared. Tried 2-star align, the same. Tried 1-star align-success, much bigger list to choose from for alignment stars. Wondered why on earth the programmer did these inconsistencies. Selected first star, slewed. Far off target. Finally realized that finder scope not correctly attached. Corrected this. Slew speed way too low- another 10 minutes until realized that "rate" button sets slew speed also during alignment. Success. Slewed to second star, aligned. Back to first star and realigned. Back to second star - directly in the crosshairs, mount tracks perfectly (at first sight). Relief. camera mounted and connected to laptop. Start taking images. Relized that there is still some error, but significantly lower than on first try (Okay up to 10-20 seconds). Shot images for hours until Orion reached trees. Happy Next up: the mystery of tracking with second cam+PHD.... If i live to see the day that we have good weather again.

I have been reading a bit about true north and magnetic north and how aligning my mount taking magnetic declination into account will help. So my declination is 1.41 degrees west. Two questions. If I was to set my compass to this magnetic declination, I need to rotate the red arrow 1.4 degrees to the left and then light that up with the compass pointer and point my north tripod leg in that direction? Is 1.41 degrees going to make that much difference? Not sure I can adjust my compass with that degree (sorry) of accuracy. I may be approaching this all the wrong way. I can see how a mag dec of 10 degrees might make a bit of difference, but we seem quite close here in Gloucester! I used this site to check. http://www.ngdc.noaa.gov/geomag-web/#declination Cheers Mark

Hiya, I recently treated myself to the iOptron SkyTracker and tried it out for the first the the other night. I kept getting star trails (which I later realised may have been due to the fact that I had it set to half speed! Silly me!) But I also had a lot of trouble with the polar alignment and I feel that, even if I had had it set to the correct speed, I still would have been getting star trails... These are the steps I went through, can anyone tell me if I am doing something wrong? I levelled my tripod and faced the tracker towards North I set my latitude to around 56 for the UK (Perth)... am I right in thinking that Polaris should then be within the field of view if I just pan my tripod around? This is where I think I messed up, as I couldn't find Polaris anywhere and had to significantly increase the latitude to find (what I thought) was Polaris. Did I maybe not level my tripod properly at the beginning? I was in such a rush to start imaging, that I probably didn't pay enough attention when I was setting it up! I used a polar alignment app and placed 'Polaris' (in hindsight I think it might have just been a random star that I thought looked decent enough ) where it was meant to be... but I just got rubbish pictures... So if anyone has any advice, I'd be very grateful!! Also, if anyone has any images taken with the iOptron SkyTracker and wouldn't mind sharing them, I'd love to have a look! I live in a fairly light polluted area and my first target was Andromeda... not the best combination, but is it still possible to get a semi-decent picture? Thanks!

Hi there in prepping for a dark skies expedition in November last year, I discovered that the reticule in my Vixen PAS had come away from its retainers and was rattling around in the scope. I duly got in touch with Opticron (Vixen reps in U.K.) and they were happy to repair under warranty. After a couple of weeks I received delivery of the supposedly repaired PAS, only to discover that the reticule had been placed upside down in the PAS. The PAS was then sent back to Vixen UK in December, who promised that they would fix the error and ensure that the PAS was accurately calibrated. So after waiting about 4 weeks, I received a 2nd delivery of the PAS, installed the scope in my SXW mount, and set about checking the calibration again, only to discover that the calibration was off by about 30 degrees. Communicating with the rep at Vixen UK, he apologised and said that they would replace the scope free of charge. The following day he emailed me to tell me that Vixen no longer manufactured the setting circle based PAS , it has now been replaced by the new Polar Scope P-FL and that they would send me the new product instead. Quite happy with this arrangement I waited just 48 hrs to received my new all singing all dancing P-FL. This new device utilises a 3 star alignment process to achieve polar alignment. So the old PAS was swapped out and sent back to Vixen, and the new PAS installed. Familiarising myself with the new process I found that the quality of the optics in the PAS appeared to be sadly lacking. Once focused, the image of the reticule in about the centre 1/3 of the FOV was crisp, however outside of this area the image of the reticule quickly becomes blurred. The fact the other two stars involved are at the extreme of the field of view, I can only I imagine using this in the field may prove rather frustrating as you go through the iterative process for the 3 star alignment. Apologies for the diatribe, however this whole experience has led me to wonder about the quality of goods coming out of Vixen at the moment. Does this experience match with anyone else out there? Has anyone used the P-FL in the field, are my concerns needless or am I destined for more fruitless backbreaking, neck straining experiences at my PAS? Kind Regards Paul J.

Abstract : The topic of Polar Alignment is not at all new. Lot of approaches, automation tools are available. Yet, some aspects in all the current approaches drove me towards doing some more work. The key aspects of this approach are as follows. Ability to do the Polar alignment without polaris sited Relatively less complexity than drift alignment Ability to address to a good extent the atmospheric refraction to finally locate correct NCP / SCP position A good starting point for amateurs who wish to graduate towards sophisticated tools and techniques Ability to quickly verify if the polar alignment is intact after one object photographed or viewed, and the equipment is being pointed to another object. This point is mentioned in light of the fact that sometimes the polar alignment gets disturbed and the next object photographed shows star trails. This is especially true if payload is tweaked for next photo imaging. What is required? One should have a good understanding of the sky and ability to identify stars upto Mag 4.5 using star maps and basic concepts of RA and Dec. One should have Equatorial mount with ability to fine tune Azimuth and Alt adjustments. Availability of cross hair eye piece for the ability to locate the star exactly at the cross hair point. It is good to have finder scope attached and the finder cross hair is aligned with the main telescope eye piece cross hair. Please note this technique is not for the GoTo mounts which many times have Alt-Az mounts fitted with tracking motors. The GoTo alignment is done using 3 Star method. However, there are a few mounts which are equatorial design and also have GoTo tracking capabilities with RA and Dec motors. For these mounts, it is preferred to carry out polar alignment. The only point about these mounts, is that GoTo should have ability to start the RA motor ( tracking) without doing the 3 Star alignment, in other words, bypassing the steps for 3 Star alignment. The technique is based on the mathematics around the stellar current positions precisely computed. The technique suggests NCP or SCP alignment using specific pointing stars. Method The technique relies upon pairs of stars identified such that pair has same RA or same Dec. The details about finding such pairs, are given in the next section ( Mathematics). Step 1 Try to do a very coarse polar alignment using your latitude and pointing the equatorial axis approximately towards a possible Polaris direction. This is only to reduce the iterations in the method below. There is no dependency to visually site Polaris. Step 2 Select the pair of stars of the same RA from the table 1 below. Now, while choosing the pair, please select that pair which is closest to the zenith. This will reduce the error due to atmospheric refraction of siting those stars. Choosing such pair, will get better alignment. Note that the NCP and SCP lie on the same RA contour of the pair, you have just chosen. Locate the first star of the pair in the cross hair eye piece. Loosen the DEC knob of your Eq mount. Let the RA axis not to be loosened. Further, please start the RA motor and hence the tracking. In case of GoTo capability, please ensure the tracking is On, while the 3 Star alignment being bypassed. Rotate the telescope around DEC axis such that the second star of the pair is in the Cross hair eye piece. In the first attempt, the second star almost certainly will not be at the center of cross hair eye piece. And you need corrections. At this point, take the help of the finder with its wider field of view. Identify the position of the second star whether it is below or above the finder cross hair. Adjust the Azimuth of the mount through the coarse or fine depending on how off the second star has been. o Tip : In case, someone is facing difficulty in finding which direction to move Azimuth of the mount for correction, the following tips may be of use. A simple way to determine is to locate where the second star lies with respect to cross hair. Assume it is on the lower side of cross hair. Then the correction in the Azimuth of the mount should be such that the star is moved upward. It may be noted that your finder can be either inverting or non-inverting. Now, to determine the movement, please hold the finger on the lower side in front of the primary of the finder. And slowly lift the finger towards the center of the primary to obstruct it and continue moving upward. While doing so, please observe from the eyepiece. The blackish ghost image of finger will be seen moving. If movement is lower to upward, the optics is non-inverting. If ghost image moves from up to down, it is inverting. With this small trick, you would know how to apply correction. Once the correction is done, please point the finder to the first and then second star alternately simply by rotating around Dec axis of the mount. Both stars will be seen at the cross hair. At this point, coarse polar alignment is done. Now, please use the main telescope cross hair to locate the first and then second star using Dec axis movement. If required, please carry out the necessary Azimuth correction. Again, please use the above small trick to find out more on how to apply correction. At this point, please note that at the telescope’s high power ( with cross hair eyepiece), the Dec axis is correctly tracing two stars in your pair. Note that NCP/SCP lie on the same Dec axis. The Azimuth alignment of NCP/SCP is achieved. No more touching of azimuth knob of your Equatorial mount now. Step 3 Site the pair of stars of the same Dec from the table 2 below. Now, while choosing the pair, please identify roughly the midpoint of them. Now, select that pair whose midpoint is relatively closest to the Zenith. With this, one star is relatively East ward and other one almost at a same distance but Westward. This will reduce the error due to atmospheric refraction of siting those stars. Choosing such pair, will get better alignment In case you are unable to select a pair, please read Step 4. Note that the NCP and SCP lie on the centre of the Dec circle which the above pair inscribes. Locate the first star in the cross hair of finder. To locate the second star, please lock Dec axis. But loosen the Eq axis and rotate the telescope around Eq axis. Please carry out Alt adjustments of the mount. Please use similar procedure and tricks as in the step 2. Once the two stars are in the cross hair positions of the telescope, the polar alignment is completed. Step 4 ( only if you could not carry out Step 3) Site the pair of stars of the same RA from the table 1 below. Now, while choosing the pair, please select another pair which is off zenith. Please try to select such pair which has both stars approx same elevation from horizon, so that their atmospheric refraction is almost same. Effectively, we cancel the atmospheric refraction influence. Please note that in step 2, NCP/SCP is located to be on one of the RA lines. Now, we use another RA line with this newly selected pair. Again, for these stars to be centred, please keep Eq axis fixed and only move Dec axis ( similar to step 2). However this time, the mount corrections to be done are using Alt adjustments. Once the two stars are in the cross hair positions of the telescope, the polar alignment is completed. Mathematics The starting point was the star catalog where the Epoch 2000 is taken as baseline. Then I selected the stars brighter than mag 4.5. I applied the corrections due to Earth Precession and also the individual star’s proper motion. With the base data was ready for today's’ star positions. Then I programmatically picked up all pairs for same RA (within 0.001 difference) and later all pairs with same Dec (within 0.001 difference). I found mag 4.5 to be heuristically optimal. This magnitude is sufficient for visual locating these stars. Also, the number stars shortlisted from the main catalog is good enough to give sufficient number of required pairs. The pairs located today may not be valid after say couple of years due to Earth Precession and stellar proper motion. The below two tables will need fresh computation then. Disclaimer: I have tried few of the above mathematically found pairs from my location 19 Lat 73 Log. I use Bresser ExOS 2 mount. After the polar alignment, the tracking was tested for 10 min which was adequate for my current level of astrophotography. At different altitudes, different latitudes, this is not tested. I believe, the method will definitely work for small exposures. It is to be validated if this method works for very long exposures. Star Pairs Table 1 : Star pairs with same RA ( useful for Step 2 and 4) Sr No First star (name) First star HD Id Second star ( name) Second star HD Id 1 Gam Cas 5394 37 And 5448 2 Nu Per 23230 19 Tau 23338 3 Ups Tau 28024 71 Tau 28052 4 90 Tau 29388 53 Eri 29503 5 Kap Lep 33949 Rho Ori 33856 6 The Aur 40312 Del Aur 40035 7 Gam Mon 43232 Eta Gem 42995 8 Eps Gem 48329 30 Gem 48433 9 13 CMa 50013 V0415 Car 50337 10 Omi CMa 50877 The CMa 50778 11 P Pup 63922 Xi Pup 63700 12 Chi Car 65575 11 Pup 65228 13 Del Hyd 73262 E Vel 73634 14 B Vel 74180 V343 Car 74375 15 Iot Cnc 74739 Eps Hyd 74874 16 31 Leo 87837 Alp Sex 87887 17 Pi Cen 98718 Sig Leo 98664 18 Lam Mus 102249 Nu Vir 102212 19 Alp Crv 105452 Del Cen 105435 20 Gam Cen 110304 Gam Vir 110380 21 5 Boo 120477 2 Cen 120323 22 SHT 56 129116 Alp Lup 129056 23 Del Her 156164 Pi Her 156283 24 102 Her 166182 Pi Pav 165040 25 110 Her 173667 Phi Sgr 173300 26 Zet Cap 204075 Gam Pav 203608 27 Del Gru 213009 Del Cep 213306 28 Iot Cep 216228 Mu Peg 216131 29 Bet Peg 217906 Bet Psc 217891 Table 2 : Star pairs with same Dec ( useful for Step 3) Sr No First star (name) First star HD Second star ( name) Second star HD 1 7 Cam 31278 Gam UMaj 103287 2 Iot Cyg 184006 The Boo 126660 3 H Persi 26630 Dmi?? Cass 4180 4 Pi Aur 40239 Iot Her 160762 5 39 Cyg 194317 Omi Persi 23180 6 Eta Peg 215182 Zet Cyg 202109 7 Iot Cnc 74739 Bet Tau 35497 8 Bet Peg 217906 Vet Cyg 183912 9 54 Leo 94601 Alp Vul 183439 10 Alp Tau 29139 Gam Gem 47105 11 Mu Ceti 17094 Lam Ori 36861 12 Omi Psc 10761 Bet Cnc 69267 13 Pi Ori 30836 Del Hyd 73262 14 3 Agr 198026 Lam Agr 177756 15 Iot Ori 37043 Iot Vir 124850 16 Lam Eri 33328 Eta Eri 18322 17 The Lib 142198 Del Crv 108767 18 Bet Cet 4128 Bet CMaj 44743 19 88 Aqr 218594 Pi Sgr 178524 20 88 Aqr 218594 Xi Oph 156897 21 4 Xi CMaj 46328 3 Eri??? 18978 22 Rho Pup 67523 Omi CMaj 50877 23 Omc Cau??? 56139 61555 24 Bet Hyd 103192 43 Eri 28028 25 2 Cen 120323 Eps Sgr 169022 26 Alp CrA 178253 Mu Seo 151890 27 Bet CrA 178345 Lam Gru 209688 28 Phi Cen 121743 Eta Cen 127972 29 Eta Col 40808 73634 30 Vel 78647 Gam Phe 9053 Good luck Ashirwad Tillu ( ashirwadtillu@gmail.com), user name ( antariksha)

POLAR ALIGNMENT IF THE POLE STAR IS OBSTRUCTED (e.g. OBSERVING ON A S-FACING BALCONY!!!) Set up your scope on the floor (assuming it's reasonably level) in equatorial mode, with a rough guess at North. Put the tube into whatever 'home' position the instructions specify, or that you have chosen. Now choose an easily recognisable bright star at mid altitude. Pretend you HAVE polar aligned, and tell the scope to go to this star. When the slewing stops lift the scope very gently and turn the mount round till the star is in the centre of the field of view and you should have a fairly good polar alignment. If you are for example videoing planets and can also autoguide, this alignment may be all you need. But you can now refine it by the drift method if you need to - see https://www.skyandtelescope.com/astronomy-resources/accurate-polar-alignment/ This method should be quite useful for Southern hemisphere observing, where the 'south pole star' - Sigma Octantis - is difficult to find especially in light polluted skies. And of course my advice here applies if you have a North-facing balcony!