sorrimen

Hi all Just received a used Baader zoom mk3 for a nice price. The eyecup on it is very flimsy, and at full extension it wobbles about. Can see it being annoying at the very least. Have seen a couple others face this issue and just wondering if anyone has any ideas on DIYing a fix, or if it’s worth sourcing a replacement eyecup (£15 or so, but fear that it may be(come) just as flimsy). I’ve thought about widening the rotating eyecup to make it fit firmer, perhaps by sticking a layer of paper to it or something similar. Have also thought about letting a drop of superglue dry on the small sticking out clips to make them sit in the grooves better. Thoughts? Cheers Ross p.s. images attached, just in case anyone is unfamiliar with the design/hasn’t seen it in a while.

Cheap(ish) skywatcher one works well enough for me, as an example. Bahtinov only works on point sources, so could be used on jupiter’s moons but nothing works better than focusing using surface details I’ve found. Can always try Bahtinov first!

Many targets last night. One of which jupiter with a nicely placed GRS. Must admit that my eyepiece train got a little ridiculous…. Also saw a very interesting break in the clouds, with a ribcage running through it.

What a night tonight was! Not the steadiest seeing or notably incredible transparency, but I was lucky to be joined by @PeterW. Needless to say, in the 3 hours we were out there he showed and taught me a whole lot (much more than I thought possible). Got set up at ~9:00pm with the 8” dob. Thanks to Peter, solved a recent collimation issue I’d had so we were up and running whilst the scope was still cooling off. First stop was Jupiter, which wasn’t bad but there wasn’t much to be seen. Headed quickly over to saturn, which took higher mags much better. 150x, division was just visible in outer parts of the rings. Pushing up to 200x and 240x, division was much more visible and Peter pointed out the shadow of the planet on the rings, which was much easier to see than I’ve noticed before. I started off the DSO viewing with the ring, as it’s one of my few stellarium-free objects which I can find nice and quickly. Tested out my new ultrablock, which at 100x helped contrast a little and the ring structure was of course easily visible. This is where the fun began, with Peter leading me on a marathon with tonnes of firsts. In a rough order, we hit M15, M2, M11, M25 (possibly 24?), Coathanger, M27, Double cluster, Albireo, M31+2 and various others along the way. M2 and M15 were similar, with more resolvable stars to me in M2. M15 was more of a ‘diffuse’ glob than the M13 I’m used to, which I very much enjoyed. M11 was a very fun target to explore. Going up in mag to 100x and 150x resolved more stars, with one very notable faint star that would pop in and out with averted. M25 and the coathanger were treats, with their own interestingly shaped offerings. M27 was the poorest showing that I’ve seen of it, likely due to some high clouds rolling in. With the ultrablock and 75x, it improved significantly and became much more of the usual object I’m used to seeing. Gave M71 a go, but I’ve only ever got it on extremely transparent nights from our poor bortle 7. No luck there. Speaking of no luck, we also went over to the veil to see if anything could be seen with the ultrablock. No surprise that there was nothing there! Embarrassed to admit it, but I hadn’t seen the double cluster or albireo before. Albireo was exactly what I’d expected to be, but much less tight of a double than I’d imagined. The colour difference between the two stars is just fantastic. The double cluster was brilliant. Was surprised to fit both in one 24mm eyepiece and will certainly be revisiting this often. Plenty of stars to see, especially in h Persei. Can’t imagine what this would be like from darker skies! Swept over to M31 briefly as clouds were rolling in. M32 pretty easy as per, but no detail in either as expected from the LP and transparency situation. Glancing at stellarium, I noticed the GRS had come around so we swept back over. Wasted a bit of observing time to try out my new ADC, which thankfully reached focus without issue. Seeing had steadied out a little, but 150x remained the best mag. Great amount of detail to be seen, notably the swirling around the GRS and the north and south polar regions. Finished up with Pleiades and the moon. Moon benefited greatly from the Baader zoom provided by Peter. Some great detail, with plenty of central peaks visible within craters. All in all, a fantastic time and a great pleasure to share the night with Peter. Tonight has really opened my eyes up to what else is around!

Wow! That is one hell of an image. With 114mm aperture?!! Attaching the adapter and you’re onto some phenomenal shots.

Motivating indeed! Glad you’ve managed to get first light and a real promising start. Can assure you that my first attempts didn’t come close to this and improvement is exponential in the first few sessions, so it’s up and up from here. Can’t wait to see what more you come out with! p.s. looks like you may be a touch out of focus. I know just how hard it is to tell in live view, but any cheap electronic focuser is a godsend for our sort of imaging if you don’t have one.

Not quite what you’re after, but have you tried taking off the rubber eye cups? It makes it a whole lot easier to centre etc. and you can the screw up and down the eyecup holder part to find the perfect distance without having to adjust it on your NexYZ. Worth a shot!

Digressing a bit, I think you may be entirely correct logically, though I’ve had quite a think and I keep coming to different conclusions. It would depend on the ROI being representative of different pixel sizes, and in practice I think an identical ROI (even with different pixel sizes) appears the same size on your screen, but with twice as much focal length the image is twice as large despite you getting the same amount of detail, so it’s much harder to track and get sufficient frames. I think this is more likely as your computer screen pixels can’t change size so it would simply reflect its own 320x240. I could certainly be wrong though, and if ROI on your screen does indeed reflect a different sized pixel then you would be 100% correct. The caveat is also that your file sizes would be larger as you’d have to up your exposure to compensate for the dimmer image, also resulting in lower FPS. Sorry to Nic for hijacking the thread, but I’ve been racking my brain about this for the last 10 mins!

With camera + barlow you should be able to reach focus. I am just about able to with the 8” dob and asi224, but if you get a low profile 2” to 1.25” adapter there is no issue at all. It’s when you add ADCs or extension tubes etc that it’s starts to get tricky!

Oh I see, that makes much more sense bit silly from me! But yes, it takes a fair amount of processing power so wouldn’t imagine the app store would have anything.

678 undoubtedly. The lower read noise in the 585 won’t come close to the difference between optimum sampling and significantly undersampling. Even if you struggle with 3200mm, the closer you are to optimum sampling the better.

Just to answer your question specifically about 4x and manual tracking. In my own experience with an 8” (not sure whether this would be easier or harder than a 14” to manoeuvre in practice), 3000mm fl really is the upper limit before you’re just losing far too many frames trying to let the planet drift. It’s not so much that finding the planet is impossible, rather that getting enough complete planet frames within 3 minutes in a smaller ROI to enable higher FPS. This is my own advice from my own experience, so YMMV and it could be worth trying a 3x with an asi462 and being at optimum sampling. I would have to slightly disagree with catburglar above, as even though your level of detail would be the same with the 4x and 4um pixels, it would be virtually impossible to get the planet on the sensor, let alone on a shrunken ROI to get sufficient frames. Also, a word of warning that pixel size isn’t the only consideration. If you find a camera with small enough pixels, there’s a chance it may not have planetary level FPS or low read noise. With your set up, there’s always compromise, just as there is with my manual 8” dob and asi224. Best of luck

Important to note is that you will always want to cut down your ROI for planetary, so having a huge sensor is a bit of a waste. I would say ~3000mm focal length is really the upper limit for manual tracking at a sufficiently shrunken ROI (800x600 or lower). Pixel size is not something you should consider just by looking at the size; it has to match your focal ratio. Given that you’ll be using a 2x barlow at most, and perhaps a 1.5/6x by screwing it onto the nosepiece, you need to find a camera that matches your resulting f/ratio by multiplying the pixel size by 5x. I.e., if you’re imaging at ~f/10 with the 2x barlow, you’ll want pixel size of 2um. The problem is most planetary cameras have pixels much larger than this because planetary favours slower scopes (larger image scale given the already bright target). Apologies that I haven’t suggested specific cameras, but focus on getting one matched as closely to your imaging f ratio as you can, along with a sufficiently high FPS and low noise.

Hi Roger Good progress, every new image from you is better and better. On the off chance you misunderstood, Geoff meant using Jupiter’s moons rather than the moon. You’d probably have to increase the exposure for a second to get good focus, but after than you can lower it and do tiny tweaks using the visible planet features if needs be. Side note: an electronic focuser is invaluable for planetary imaging. Gets rid of the image shake as you don’t touch the scope to focus and even the cheapest options will work wonders above manual focusing. Also had a brief look at your settings. One glaring issue is that your FPS is capped at 60fps. Make sure you set this to uncapped. Loving these posts, so keep em coming Roger! Ross

Looking forward to those images!

Great picture, and more importantly great progress! Really getting some good detail and it’s always nice to get the GRS in. Is there a reason you’re going for linked wavelets? They have their use, but I’ve often found that using the ‘sharpen’ and ‘denoise’ buttons mainly on layer 1 (crank the slider all the way), with minor increases to layers 2 and 6 get me 99% of the way there and are much easier to use as someone just starting out. Increasing that layer 1 denoise button a couple times can do wonders to cleaning up my images. Keep it up! Ross

You could potentially do some solar system AP, but god knows how you’d attach the iPad to a scope. If you mean wide field shots of the sky, then it’s easy to just do a long exposure picture. What you won’t be able to do, is take multiple long exposures tracked for stacking, which is really what AP is. Absolutely all AP starts with the mount (apart from untracked planetary).

Absolutely fantastic. An incredibly enjoyable read and wonderfully supported with the images. Just goes to show how much joy and wonder you can get from only one target. Thank you!

Oh great, that saves me some worry. I’m praying the additional 40mm or so of infocus with a new standard adapter works out. Thanks for following up.

Cheer, Craig. Having a real headache over this one 😆 That seems like a good idea, though I’ve seen a couple of posts saying the ADC body itself is 30mm which would change the calculation a little. Either way, my best bet is probably to leave you folks alone and utilise FLO 30 day returns to see what works best! Thanks again.

Oh god that just adds to the complication! Would you think it’s significantly larger enough to cause off-centre issues with a standard 2” to 1.25”? Just having tested it, the wiggle room with the asi224 (my only 2” test) is no greater than the supplied 1.25” adapter, so in the very least it doesn’t seem that the Synta one has compensated for the diameter and it wouldn’t be much, if any, of a downgrade centring-wise. Would be ideal to avoid having to scout out two sufficiently low profile adapters.

I experimented with this as the camera has a 2” slot, but sadly the barlow compression screw sticks out further than 2”. Very useful tip though.

Hi all Very niche question here. I’ve been imaging with a 2x BST shorty barlow but have the option to buy a used 3x Xcel-lx to get to optimal f-ratio. Currently my 2x + camera focuses very very close to the bottom of the focuser, so I’m wondering whether the 3x will push the focal point backwards or forward. I understand that this may depend on the barlows in question so have included them in the title, but if it’s just a matter between 2x and 3x even better! TIA Ross p.s. I’ve put this in eyepieces rather than imaging because I would imagine more people browsing the eyepiece and barlow topic would have experience with the two focal points than in the imaging topics.

Definitely a case of deals between manufacturers. Makes no sense to prioritise AP in a manual dob, not to mention the balance and EP position issues it introduces. Have you seen anything about cheap adapters with compression ring style locks? I can’t imagine it’s something you can get very wrong but with my eyepieces all having undercuts I don’t want to skimp if there’s well-known risks to the cheaper designs. Certainly look appealing with the £10 price tag and extremely low profile.

Being able to screw on the barlow directly would definitely help, but sadly mine doesn’t have the functionality. The stock SW adapter seems to extend ~50mm out from the top of the 2” top, so I’m hoping with a very low profile adapter I should gain enough to use the ADC. Just a cheap one on ebay seems to only extend 10mm above the 2” top, so I’ve got faith.