Quetzalcoatl72

I was trying to image planets last time with my RC6 stellar lyra scope which I've never had much use out of it, it's been a long time since I imaged something(march I think) but I did remember to set up everything correctly I think. My camera of choice was the asi462 planetary camera, I polar aligned to the best I could and I aligned my finderscope to the best of my ability(which I really hate because there's 6 bolts and trying to get a star centred whilst having said bolts tightened and making sure the star in the scope itself is also centred is near impossible for me) but it looked central to me.

I moved to a star and it was in the image which is a great start (using Sharpcap), so I centred it and moved to Jupiter(which wasn't centred annoyingly), took a while finding Jupiter, I followed the bright spike of light on the image to see it. I imaged that and got a decent job out of it, then I realized at 2am mars was out so I got excited and moved to there, for some reason I could never find it on my computer screen no matter how much I tried to use the keypad manually, same for Uranus which I guess is a harder target. I'm also using a 2x barlow.

I am using N.I.N.A and I tried to plate solve but ASTAP said there was no stars despite there being many after a minute exposure at least, it also said astrometry.net wasn't working either, I've always been having on and off problems with plate solving for a while, oh and as a side note, my dec is having problems where it struggles to turn on rates lower than 3, there's a slight knocking noise, I don't know whether the worm is too tight or loose. I'd love for any help on this would be great as I intend to go out with my scope in a more darker area and I don't want any hiccups there. Thanks!! oh and I've attached an image of my results for the first time with this scope

01_54_45_pipp_g4_ap639.bmp

To avoid spending 10's of thousands on multiple cameras I just want one unmodded camera that I can clip filters over the sensor so I can use it for deep astro, general landscape and my other macro and micro hobby. Budget of no more than £1k, It has to be mirrorless to avoid any vibrations for my macro. Preferably canon as that's been my go-to brand but if any or brand truely beats canon with my needs then i could give that a go baring in mind i have a sigma 100 macro lens which is canon fit. There's so many conflicting stories and reviews out there, I'm not tech savvy as numbers and techy talk confuses me I just want the honest truth, Thanks.

how is it always still there? is it a one off? i dont get it, how can an object move back to where it was so others can see it again?

I found many unnamed objects when looking for something different to try on this software such as the headphones nebula and this huge one I found(see attached) There is also a lot of objects that are named but there's no reference image so I don't know how big or small they are for framing see ic2144 on this image. It said I had 5 of 9 star catalogue but I clicked download and it gave me the errors you see in 'extras'. If anyone would point me in the right direction to get stuff i need to download and how to install would be great thanks. Also as for this large nebula I'm interested in does anyone know if its visible with any of my setups? and the bortle 7 I live in, seems faint already on the reference.

3 minutes ago, Space Oddities said:

I think you're using the wrong spacers between the camera and the flattener. The one with 3 screws is designed for an eyepiece, not a camera. I'm pretty sure this is causing the coma.

This is what you need to reach 55mm of back focus:

Tip: you might want to place the 21mm before the 16.5mm spacer, unlike the diagram above. It will work better with the Askar's rear T2 mount!

Some documentation:

http://www.askarlens.com/index.php/class3/186.html

https://astronomy-imaging-camera.com/tutorials/best-back-focus-length-solutions-55mm.html

Thanks, I used the 1.25" because i could put a filter on there and it was easier to take out instead of screwing it in. But i now put a filter on the front of the scope so i'll try that out before i waste any more imaging tonight. I'll let you know thanks!

I've included a 5 minute exposure one at the start of my session and one recently after I've messed around with it, I'm starting to think it's amp glow too, that red light on the corner seems to have sucked it out of the rosette since it was fine at the beginning. However the 533 is designed to have no glow a all.

2022-02-27_20-11-51__-10.00_300.00s_0003.fits 2022-02-27_22-13-58__-10.00_240.00s_0019.fits

42 minutes ago, Adam J said:

Would be useful to see a picture of both the image / stars and how you have the scope setup? For the record it's not designed to be used at 220mm for imaging. You can only image with the corrector reducer. 

Adam

I'm out with it now, i hope you can see what's going on, i just made myself a hood because the neighbours are huge light polluters and they aren't the negotiable type. The pics are in fits format so I can't see them until I start loading them into a stacking software, I'll copy an image over in a bit. I use my ed80 as a mount for the 180, it's embarrassing but i only have a neq6 and i can't put it on it's own it's too light. but thats another problem on it's own to sort out at some point.

How do I fix the coma's on this thing? the 220 is horrible so it's a 180 scope atm, I put a lp filter on the front and I think I made it worse, tried the rosette and only a few stars in the center are perfect circles. I'm not using any of the extention tubes just the reducer and reducer extension tube.

On 25/01/2022 at 20:09, michael8554 said:

As in your previous NEQ problems, diagnosing without a GuideLog is just guesswork.

But from your screenshot, before the DIther, Dec did not need any guiding, so PA must have been pretty good.

As soon as Dec guiding was required following the Dither, PHD2 was failing to pull Dec back.

Because of Stiction in Dec at a guess.

Michael

I managed to get this on the night i started this thread regardless of some eggy looking stars, i think i ended up setting dec to guide north only

On 25/01/2022 at 19:08, teoria_del_big_bang said:

If it is similar to the HEQ5 there should be two taper bearings inside one on the dec and one on the ra, if you replaced those you have to be super careful how much pre-load you put on them when tightening the nut that brings the two halves together, it really is just a tad (I mean a tad) more than hand tight otherwise the axis may still be smooth but the extra pressure will mean the axis stalls very easily, although more noticeable if you slew it at full speed I suppose a quick sharp movement when dithering could cause it to stall and may then interfere with the tracking.

Is there any chance you have replaced these and over tightened them ?

In the HEQ5 they are as below.

Steve

 

I just cleaned and re-greased them. I replaced the smallest bearings that are on the worm shaft, which i recommend btw the old ones aren't great, it has thin metal rings that can easily get dinged up, the new ones i put in are rubber and they turn a lot smoother

10 hours ago, teoria_del_big_bang said:

Surely the problem is the amount of backlash in DEC.

In daylight with power on but not tracking can you physically feel any movement in DEC if you twist it by hand ?

Can you take the cover off to look at the belts, does anything look odd, could they be slipping, start it off tracking with cover off see if you can see anything odd, can you move anything with your fingers that can cause this backlash ?

I have a belt modded HEQ5 I can take covers off and watch it track I am assuming the NEQ6 is similar ???

Steve

no the neq6 is a pain, you can't see anything unless you fully dismantle, but then there's no point because nothings connected. The mount also never had a belt, I modded it to have one installed and it worked great. Both dec and ra are stiff when locked up. I recently changed the bearings because they were damaged, everything physically feels solid and smooth... however i notice slight knocking when it it making the corrections in guiding.

everythings fine in those dummy departments, do i really need dithering?, people say dither or die so i dunno

1 hour ago, teoria_del_big_bang said:

also why do you have so much backlash in Dec.

Steve

I don't know, that's what i'm trying to figure out

heres the graph

I just want to guise 4 minutes thats all, i've done it before but now it's acting up, seems like ra and dec are way off than what they should be, i've reset everything and ran the guide assistant, but i'm still getting slight trails. Good balance and polar alignment etc i have im sure. I'm not sure much about the balance i was told to have it slightly east heavy, i'm currently pointing at triangulum. Can anyone figure this out thanks

I know people use this for star trackers but has anyone actually tried to put it on a large scope like the neq6. I currently mount it on the ed80 and just use that, but it seems a waste to bring out the ed80 and not actually use it because the askar is too light to have any counterbalance. i think the bar is actually heavier lol.

Edit: oh thats right i need a guidescope, i might get away with using one weight right to the top if i create a setup somehow.

5 hours ago, Adam J said:

It threads onto the front of the scope in front of the objective onto the same thread you used for the lens cap. To be honest its the best place for it you should not get reflections and you should not get any issues with pass band shift. Clearly its exposed to the elements though so I use a dew shield i made myself to protect it in use. Finally it wont cause any flats issues with dust on it etc from that location. 

Adam 

Great, yeah! does having dew shields cause vignetting, i don't have one but if i position my dew heater right it should be ok hopefully

Has anyone used a 2" filter with this scope? I don't want to have spend another 100 on a optlong pro lp filter for the 1.25". Anyone know how I can fit it in-between my asi533 and askar?

9 minutes ago, Phillyo said:

Astap works perfectly for me within NINA so I think you may have some settings wrong.

Ok it somehow worked perfectly for cats eye, it's definitely temperamental, I wasn't able to calibrate my PHD2 because it was well above the -20/+20 range so i went to spider nebula and It didn't work. My scope is 1600fl so i have to take 20 sec exposures, could it not be enough? The thing is, entering the co-ords in manually should take me there anyway, but sometimes it doesn't maybe that's a problem with stellarium?

4 minutes ago, ONIKKINEN said:

Tolerance settings changed for some reason? I have mine on 0.5 arcmin and it is always centered, but sometimes takes several tries to get there. If it takes more than 10 tries however NINA stops the platesolve-reslew sequence and just hopes its on target and shoots. If you have the retries set to a low value like 5 and you get gusts of wind or something else you could run into the retry limit. ASTAP is quite picky on starshapes, if its windy my platesolving fails with the EQM35.

I changed it from 1 to 0.5 nothing changed. It is actually a bit windy at the moment, you're right, nina doesn't retry because it thinks it's there when it's not. I just don't understand why entering the co-ords manually doesn't work when it should

I use NINA and in that program i have astap as my primary and secondary is astrometry.net. In the past i've always used astrometry because astap just refused to work. Then sudden astap started working really nice, my targets were centered, but now it's always off by quite a bit. I have to manually move the scope to the correct co-ords using stellarium, and even sometimes that's not accurate. It feels like it's to do with the degree in the sky i'm pointing too. For instance astap will go to bodes, roughly, and m101 too, but not properly centered however everything else the object just does not appear on screen. I have recently stripped my mount apart and fixed all of the physical issues i was getting like binding and chainsaw noises, now they sound smooth and i'm happy with it. But i just can't get astap to work for the life of me, Is it out of date now? Did i accidentally change any settings without knowing? I'd like to know how i can fix it, thanks!

On 09/01/2022 at 09:34, teoria_del_big_bang said:

As @tooth_dr says just dither for lights.

The idea is that whilst the camera is taking an image the scope follows the target perfectly (or as well as it can within the limits of your guiding) but then for the next image it just moves the scope a little so that the next image is a few pixels over one way, then the image after that it will move it a few pixels  in another direction. 
So over a session it will keep dithering around a position never moving more than a few pixels from where you took the first image but not taking all images in exact same position.
So when it comes to stacking the pictures together it will line up all the stars but any hot or cold pixels will not all be in same position on all the frames and so the software in the stacking program can remove them.

I thought that was the case, I'd like to keep the images centered especially if i want to capture multiple objects at once like galaxy clusters

On 09/01/2022 at 16:19, ollypenrice said:

Darks can't see out of the scope so there's no point in dithering those!  As Steve says above, if using a fixed light source for flats you don't need to dither. If you're at all worried that your light source is uneven you could move it around a little or rotate regularly during the capture sequence but that's unlikely to be necessary. However, picking up stars is indeed a risk if doing twilight flats. Leaving a few seconds between flat exposures will, if the mount is undriven, give you natural dither as the stars move. It will also stop your chip heating up which can sometimes happen with flats.

Olly

My flats are done with the screen and t-shirt method, the dust picked up looks like rings, the pictures are still dark gray, i've seen a lot of light greys or even other colours like pink. I don't know what the deal is with that, and I hope my flats are addicuate.

5 hours ago, michael8554 said:

From your lastest GuideLog.

All your Calibrations had about 15 to 20 steps of Dec Backlash clearing before the Dec part of Cal commenced.

Here's one of your Dec Cals:

 

 

Resulting in very different RA and Dec guiderates, as reported after each Cal:

Cal Dec = 43.2, Last Cal Issue = Rates

Norm rates RA = 11.5"/s @ dec 0, Dec = 3.6"/s;

Your mount was set to 7.5arcsecs/sec on RA and Dec.

For your very last of many Cals you moved down to close to Dec =0 and then guided for about 5 minutes with okay results:

RA = 0.62  Dec = 0.72  arcsec.

You had Dec guiding switched to   DEC guide mode = South.

Which was true at midnight when you did your only Guide Assistant run, but by 02;00 that was no longer true, as by then Dec was drifting south, so needed guiding north !!

So for most of the night Dec was unguided, resulting in huge uncorrected Dec excursions at times.

Luckily your PA was good enough that no corrections were required on that last run, hence the good Dec figure.

The procedure is to move to your target, switch off guiding and see what way Dec is drifting over several minutes, set Dec guiding to correct that drift.

So bottom line, you need to pulse north a lot more before Cal, until you see equal star movements for several pulses.

An even better solution, adjust your Dec worm and bearings !

And guidescope focus is still poor.

Ok, I understand that much appreciated! Yeah I think I'll get a matching pair of new bearings for dec as well as making sure the worm shaft is the same at the other. Think the guidescope is a bit grubby, I also struggle with focus without a mask so i'll need to get one of those in the future. How much more accuracy will I get with calibration if i have pure focus? Also from what I see in the stats the RA is fine? in regards to performance, both sound fine as in no grinding or play when they're locked up, as I say before the DEC is stiff, which could also be the problem with backlash?

16 hours ago, michael8554 said:

Really ! Seems fine ?

Sounds like you haven't read the PHD2 instructions if you don't understand that.

Use the handset buttons at lowest slew speed, or the PHD2 Manual Guide with 5000mS Pulse setting, to move the mount north until the guide star actually moves on the screen.

Then the Dec Backlash has been taken up.

Then you can get a realistic Calibration.

Again, it's all in the PHD2 instructiions, you just need to read them.

Michael

Sorry I'm a bit slow when it comes to techy stuff and I struggle with retaining information. I tried to follow your advice as best as i can and came up with a new guide log, this time I know it's worse, I first looked at an object to the south about -1 degree, cleared the cali data and manually pulsed north at 5000 until the star moved as you said, then i started calibrating. I also tried at +30ish degrees south, sadly these methods didn't give me 4 minute guided exposures the stars trailed off a bit to the right of the image. The other method at 30-40degree was less dramatic, and i did a third calibration where i just went to Procyon and that yielded better results but still wasn't perfect. There's another in the logs that should be ignored as the clouds rolled past and lost the star.

Before I packed up I tried no guiding, sadly i couldn't get 3 minutes, it trailed off slightly but ended up better than after trying the first 2 calibrations. This may be due to balancing issue because I try to make it east heavy but when it flips the other way I forget to make it weight heavy instead, not sure though.

PHD2_GuideLog_2022-01-12_233242.txt

20 hours ago, michael8554 said:

So get your new bearings in and the worms adjusted, and post the new logs.

Michael

Nice, thanks, interesting info! So i replaced both the small bearings in the RA, ideally I should have did it for DEC too but I didn't want to take it apart as in my eyes I had no problems with that, backlash etc. just a bit stiff! I found other problems that must have been the cause for RA such as loose grub screws on the motors spindle(no idea how that happened) The worm shaft was also loose and the bearing wasn't even in all the way which is why i couldn't get the end cap on fully, the DEC also has that problem but doesn't bother me and it seems fine. I did 2 full rotations on both, no grinding, no chainsaw noise, it worked! I plan to go out thursday so I need to figure out what i'm doing in PHD, but before that my polar scope probably needs adjusting, i've never did it before. Sharpcap gives me decent polar alignment anyway. 

I don't really focus the guide cam, i just make sure the stars are big enough for sharpcaps polar alignment, what HFD value should it be?
What do you mean by calibrate near dec=0? and how do i pulse the mount?