catburglar

I’ve not used one, but I do think there’s a role for them…Very few objects appear ‘jaw dropping’ in a typical amateur scope when you first start in astronomy…The moon, Saturn and M13 were probably those objects that I remember thinking ‘wow’. As you grow in to the subject you come to appreciate the significance of what your seeing in the grey smudges… I think these electronic telescopes increase the number of ‘oh wow!’ objects and could certainly keep more people sufficiently engaged in the hobby long enough that they get to a stage where the have a deeper appreciation of it. That said- for me the Unistellar eVscope is a more interesting proposition- although the images are not as good as the Stellina. The ability to easily take part in citizen science project opens up a range of possibilities in a similar way to zooniverse and SETI that might appeal to those who want more than just a great visual image…

I’ve had a look this morning…the worm and wheel look nice and clean… But I found this inside…couldn’t find where it came from…It’s machine at one end but not the other, so it looks like it’s broken off something …everything still seems to be working…so it may not be ‘serious’…but will see how things go

I haven’t taken it off the pier yet, but I’ve just deleted in RA with the OTA vertical…and I get the same noise…but only when I slew from SW through S to East….going in the reverse direction it’s silent (we’ll apart from the coffee grinder motors). I’ll have to take it down at the weekend and have a proper look

Michael- thank you. I think the balance should be OK- it's in pretty standard trim with just the autofocuser, diagonal and 8x50 finder , but I'll double check the slewing with the OTA vertical. It sounded like a metal object was "ringing" as a result of unwanted vibration rather than anything related to the worm / wheel- but since that looks to be an easy thing to investigate I might as well have a go at it (I'm unlikely to break it if I'm not going in to the guts of it...). Regards John

I don’t know if you’ve tossed the coin yet. I had an AZ-EQ5…It had some play in the RA/AZ axis…It did work in AZ mode, but it wasn’t particularly quick to switch between AZ and EQ, so I ended up using it in EQ mode almost exclusively…Also…the skywatcher/SynScan alignment process seems a bit old tech, and there’s no good way using the hand control to improve the mount model for go to(the sync option seems to replace previous sync points rather than add to them)…So if I was doing it again I think I’d go Celestron or iOptron unless you really need the EQ mode

Off topic- sorry- but that second image and the context of your observing site is a very compelling advert for night vision astronomy…if only it wasn’t so damn costly and complex😁

As many of you- I’ve managed to get 4 long observing sessions with my scope (Alt-Az mounted LX200GPS) over the last week or so. On the last two sessions I’ve noticed a bit of noise when it slews in Az- not the coffee grinder sound of the motor, more like some slight rubbing together of parts leading to a ringing sound. It doesn’t cause the motor to strain, and the slews are as accurate as ever, but I’d like to get it sorted before it becomes an issue. I’ve had a look at SCTelescopes, but none of the links work, so it looks like they may not be in business. Orion Optics offer a ‘fettling service’ but it seems more focussed on optical cleaning and basic mechanical tweaks- so not sure if they look at this sort of thing. I could have a lash at it myself…but let’s just say…that’s the option of last resort😬. Any ideas/suggestions- or should I just wait to see if it persists when things warm up a little?

I chose to have a go at some tricky multiple stars tonight with my 10 inch SCT. The seeing was not quite up to the standard of last Friday, but it was pretty stable with just a little high haze. I warmed up on some of the old favourites, Castor & Wasat in Gemini, Theta Aur, Gamma Andromeda, and Sigma Orionis and Iota Cas. Having confirmed that the seeing was "in the right ballpark" I headed over to my first test of the night -7 Tau. My last attempt was spoiled by heavy dew on my corrector plate, but tonight (in spite of the haze) there was very little dew formation and I was pretty hopeful. Centring the star in an 18mm ortho (138x) I could clearly see the C component separate from the AB pair. At 250x, there was a hint of duplicity with a single elongated "airy disk". Upping the magnification with a 7mm ortho (357x), there were two airy disks with a sliver of clear black space between them, encircled by an oval first diffraction ring. Having succeeded on the first target, I upped the ante with Dubhe. Until a couple of months ago, I didn't even know this was a double...It made it onto my "must see" list after following one of the threads here. I've had to wait because I have a poor horizon to the North with obstructions and heat plumes. I thought tonight could be the night...but I was disappointed. I wasn't even able to get a stable view at low magnification - I'm guessing because of heat plumes- the seeing was certainly worse than anything I'd seen in the East and South. It's still not quite as high as it will get, so I'll get another chance, but it's getting too late- I've got an early start in the morning.... My last target was Sirius and the pup..I posted on Friday 14th about my success at a relatively low magnification (circa 140x) with a polarising filter to reduce some of the glare. I realise that this was a contentious observation, and as the saying goes...."extraordinary claims require extraordinary evidence"...I needed to try and repeat the experiment. And tonight I came up a little short. I couldn't make the split with the 18mm ortho. The filter certainly made it easier to achieve sharp focus and reduced the atmospheric induced dispersion, but I couldn't convince myself that I got the secondary. I upped the magnification to 250x and without the filter I could see the pup on the following side of Sirius popping in and out of view with the scintillation. Some times appearing as a thickening in one of the scintillation induced spikes and sometimes as a faint pinprick in the space between them. Adding the polarising filter definitely helped the view- again reducing the appearance of the scintillation. So the upshot is- I'm pretty sure the filter helps me because I can confidently achieve precise focus and by minimsing the appearance of scintillation my gaze is less distracted and therefore I can perceive things that are at the threshold of visibility. All in all - another rewarding night and a good start to the year- I can't remember the last time I managed to squeeze in 4 sessions in the space of a week...Can't wait for galaxy season....

Just managed to split 7 Tau this evening in my 10 inch SCT. Seeing was not quite as good as last week and the split was suspected at 250x with a 10mm Ortho. At 357x with the 7mm ortho the split was clear- two tight airy disks with a shared diffraction ring in a north / south line with the C component clearly separate some distance to the north.

The bolt and wheel are for mounting a camera to the rings- I guess for wide field astrophotography…I’m pretty sure the thread in the tube rings is a standard photo thread 1/4-20…FLO sell bolts the right size if you can’t get them locally. Are there any mount in holes on the bottom of the mini PC (some of them have a VESA mount option which is 100mm between centres I think)? You could simply print a platform that bolts to the tube rings with a set of corresponding holes for the VESA mount so you can bolt on the PC. So it should be a simple case of choosing

I used attached it to a monitor, keyboard and mouse directly for first set up- but I didn’t look for alternatives so I don’t know how straight forward it would be to do a completely headless initial setup…It may be possible, but I took the easy option😁

I run my scope with the compute stick version of the Quieter2 -Win10 & Skytools4 mostly, but have dabbled with Ekos and APT for imaging…It works fine…But the Mele has a slower processor and slower eMMC storage than the Beelink which has an SSD- so I’d expect it to run a little quicker. You may not need the additional performance, but if it’s available for the same cost as the Mele, then I think I’d choose the Beelink…

To say I was surprised is an understatement...I've always approached it with a "get as much magnification as the seeing allows" mentality...and I usually start with a 10mm for 250x...But usually I just get a bigger view of the atmospheric dispersion that comes with observing at approx 20 degrees of altitude. I'm not sure where I'd read about the use of filters, but I thought I'd give it a go tonight, so I popped it in and had a look- it was quite a modest reduction in brightness but definitely tightened up the image of the primary. I kept seeing something that looked like it might be the pup, but was in the "wrong PA" . I'd rotated the diagonal so I could get a comfier position to observe from and I'd become confused with the orientation of the field. So I put it back into the vertical position so I was getting a laterally inverted view again, and blow me if it wasn't in the right place after all. It was sometimes obscured by the scintillation of the primary, but it was definitely visible in the steadier moments. I didn't try it with the 10mm and the filter but I think I might next time. But- just thinking a bit more- the mag is probably a bit more than 138x- I've got the electronic focuser, filter wheel and diagonal hanging off the visual back- so quite a lot of back focus...I've not done the maths, but in this configuration with the primary mirror moved closer to the secondary the effective focal length is probably a fair bit longer than the specced 2500mm... Still- I'm chuffed- a bit like when I saw the whole of the veil nebula in and 80mm frac... I've just had a little tot of whisky to warm myself up before I head off to bed.

Had a pretty good night here in North Wales...best seeing for months. The previous two evenings have been cut short because of dew on the corrector of my SCT so I spent an hour or so today insulating it, and it seems to have worked a treat. I've only turned now in because there's sooo much dew on the scope and laptop that something will spark if I stay out any longer...but my corrector is still clear! Seems like my targets were similar to many posting here tonight: I started off at Ceres currently in Taurus on my way to the moon (I think I went the long way around 😉 )- nothing much to see. I managed 4 Plato craterlets (counting the pair as one only until I can split them) convincingly, with another two if I'm being easy on myself. Plato rilles, Alpine Valley- with the central rille, Hipalus and Doppelmeyer. Then on to some multiple stars - Sigma Orionis, Castor- I love this one- It's an easy split at low magnification and the stars are just so well defined with no seeing related shimmer at all- I'm sure I can see the spherical nature of them the view is so steady. Wasat, Rigel and Trapezium- I could see F but not E tonight. And then onto the nights big challenge- Sirius and the pup. The first time I've been able to split this - used an 18mm ortho at about 138x mag. I used a polarising filter to reduce the glare from Sirius but it still allowed the pup to show through- it made the split seem almost trivial and I'm not sure why I've never tried it before. Having seen it with the 18mm and the filter I was tempted to try and find the minimum mag that would split it- 100x with the 25mm plossl and I think it was still there, but 78x with a 32mm was not quite enough mag.

I have an ETX90- as @Peter Drew said earlier, the front cell (the entire anodised black portion) unscrews. If it’s tight try something like this https://www.amazon.co.uk/Strap-Wrench-Universal-Multi-Function-Adjustable/dp/B07WCMSMYX/ref=mp_s_a_1_1_sspa?crid=25TA0HWL83FL&keywords=strap+wrench&qid=1641247808&sprefix=strap+wre%2Caps%2C145&sr=8-1-spons&psc=1&smid=A2S1ECG6JQ4UGB&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExMklaTTZQSFNRSEVPJmVuY3J5cHRlZElkPUEwMDc1MzAyMkpUM0ZGN1EyMzEwRSZlbmNyeXB0ZWRBZElkPUEwMzY3MDc3MVRQMDdNUVAwVzNXRiZ3aWRnZXROYW1lPXNwX3Bob25lX3NlYXJjaF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl I’m sure you’ll e able to loosen it with a little persuasion..

My 2p bet says it’s the FOA60….hope gambling is not in breach of the forum rules

I don’t think it’s the hering illusion…if it were the leg would be straight even though it appears bowed…the attached crop with an overlaid straight edge shows that the image of the tripod leg is not straight I think it’s simply lens distortion because of the wide angle lens used and the proximity of the object to it..

I love cats… sealed tubes, no diffraction spikes, lots of back focus, more compact (although not necessarily lighter) than other designs of the same aperture make them easier to mount. Because of their compact nature the eyepiece position changes relatively little irrespective of where you point it, so it’s easier to get comfortable whilst observing. I’ve only used mass produced models by skywatcher, Meade and celestron but they’ve all produced good views… I’d like to try a premium model at some point, but the limits of what I can observe are almost certainly set by my eyes, so it’s probably a bit wasteful…

My best shot might be a Tak Epsilon 180ED with an Ethos 21- gets 4.1 degree FoV with an effective aperture of approx 140mm (80mm secondary and light losses at each reflection or air/glass surface). I’m not sure if vignetting will kill it though- specs say 44mm image circle - 60% not vignetted. If that’s linear dimension it’s only 26mm so probably going to get more than 10% drop off at the 36mm field stop of the ethos… Turns out this is a trickier problem of optimisation than it first seemed…

I’d come to a similar conclusion, however to achieve the 7mm exit pupil constraint you’d be looking for a 22mm fl eyepiece with a field stop of 45mm- not sure I can find one of those

Never done it, but this thread on cloudynights seems to suggest it’s pretty straightforwards (this is the 8 inch, but I’d expect the c925 to be the same) and reversible if you did want to sell later. https://www.cloudynights.com/topic/452009-de-fork-nexstar-8-gps/ You can also get radius blocks and a dovetail bar from FLO so you can use whatever mount you wish… https://www.firstlightoptics.com/adm-vixen-type-v-series/adm-vixen-dovetail-for-ota.html

If you’re happy with the optics & focal length could you defork it and put it on a different mount? The bare OTA would probably be around 10kg and the mount (say iOptron AZ pro with counterweight ) would be about the same. 2 smaller packages might be easier than one single heavy package?

When considering storage performance for planetary imaging you may want to look at this: https://www.jeffgeerling.com/blog/2020/fastest-usb-storage-options-raspberry-pi

Jassy Noting M40’s comment I would keep some of your budget for accessories- the book Turn Left at Orion is a really good purchase for most beginners in my view, and a red light torch too- allows you to read outside without ruining your ability to see faint things though the scope. I suspect you’ll already have hats and gloves - so you may not need those- but it is surprising how cold it gets when observing so you can almost never have too much of a good thing… I suspect the scope that has the potential to allow your partner to see the most that is within your budget is an 8 inch dobsonian like this:(https://www.firstlightoptics.com/beginner-telescopes/skywatcher-skyliner-200p-dobsonian.html) or this:(https://www.firstlightoptics.com/beginner-telescopes/stellalyra-8-f6-dobsonian.html) They’re both ‘pretty bulky’ so you’ll need to find somewhere to store them (I don’t have the exact measurements but something like say 60x60cm footprint and approx 120cm tall). They’re also pretty heavy (approx 15-20kg I expect) but can be broken down into two manageable pieces…as long as the trip between indoors and outdoors isn’t too twisty/treacherous. There are smaller versions (6 inch) in the same format, and also 5 and 6 inch in a v compact size that are lighter and easier to store/move, but need to be put on a sturdy table outside when using them. These scopes are ‘entirely manual’ in operation…i.e you have to find the objects yourself - which is surprisingly tricky at first (although the book referred to earlier gives excellent directions). If that’s the sort of challenge your partner likes then these would be a good choice. If however, your partner ‘likes a gadget’ then a computerised scope might be a good option. You’ll get a smaller scope (the diameter of the lens/mirror) that won’t have the same potential for viewing faint things, but after a bit of set up- it might show you more because it’ll find it’s location in the sky ‘automagically’. Something like this: https://www.firstlightoptics.com/beginner-telescopes/sky-watcher-startravel-102-az-gte.html or this: https://www.firstlightoptics.com/beginner-telescopes/sky-watcher-skymax-102-az-gti.html Note whilst these telescopes themselves may be smaller than the first options, the overall package will be similar in terms of storage space required because they’re mounted on tripods. Good luck.

Just realised- I didn’t link to the driver (only required for windows not astroberry)…https://www.silabs.com/developers/usb-to-uart-bridge-vcp-drivers