R26 oldtimer

As others have said, it's walking noise. I first noticed it in my first guided target, then I started dithering and never saw it again.

Haha, that's how it starts, welcome to the dark side! I am thankful for sticking a sensor in the scope just in time before the aperture fever was about to strike.

... But then came the mount fever, the cooled ccd fever, the filter fever, the pc & astro processing software fever, the....

Enjoy!

Another vote for a second hand ED80. You can get one with a focal reducer for the same price as the new opticstar, and it will be far better for imaging, perhaps even visual.

Or you can get a cheap and cheerful 130PDS.

Regardless of the mount, an adjustable chair or ironing chair will be great help. I use mine to sit at various heights or lean against the back, while standing, or just to put one foot on it, while I stabilize my body by putting my elbow on the raised knee.

So it looks like that this is what you actually need :

https://m.aliexpress.com/item/4000637525024.html?pid=808_0000_0101&spm=a2g0n.search-amp.list.4000637525024&aff_trace_key=9b4893f2508443c08db65c242553ed6e-1579111608727-00346-VnYZvQVf&aff_platform=msite&m_page_id=7577amp-UfuZRWmpDhc_EeyQg_4kCg1579547114977&browser_id=2ce6b9f96904439ba06875ab61a4aac1&is_c=N

Have you found a solution?

If not, I hope this helps :

The fact is that you already have a powerful scope(20", wow!). You could try EEVA with a zwo asi 294 or an attik infinity paired with an 8", F/4 scope and you would see more than the 20"...but EEVA with a camera and a 20" dob is going to be very (extremely)  difficult to track an object and not very rewarding fov-wise, unless you are hunting for tiny and faint galaxies. Is your dob goto with extremely good tracking???

So, if I were in your shoes, and already had considered of splashing an extra 3-5.000 £ to upgrade to a 28-30" dob, then I would definitely go with a proper NV device gen3 or gen4 (Gavstar and his gang know more about those "proper" specs). That way, there is no need for excellent tracking, big fov with a reducer or afocal, no laptop/cables, and a look-through-the-Eyepiece effect.

I am starting to read a bit on scts and there are some complex variables on visual backs, or add on focusers, as the scope's focal length changes. I am sorry, it looks like I can't help you as I am not sure exactly how these scope's work. I would suggest to open a new thread to one of the imaging subforums, asking how others have connected their cameras to a C8 edge. I am sure others use this scope for imaging with large sensors as yours, and they will give you a hint. Then you can see if you will use an off the shelf solution, or DIY one accordingly.

I see that your c8 has an 1.25" visual back. I am not an sct/mak person, but it looks that this scope is optimized for 1.25". I guess you could fit a 2" visual back or make an adapter but you will suffer from vignetting, as the inner tube will still be 1.25". Why didn't you get an 1.25" filter?

Aahhh, hmmm....

No, no forget what wrote before about sct threads. Your ASI071 has T2 threads/connection interface, right? So you can screw the above mentioned  aliexpress nosepiece directly to your camera. Then you screw the 2" filter on the nosepiece and insert it in your scope's 2" focuser.

I am not exactly sure what you mean. If you have a 2" filter, you screw it in front of a 2" nosepiece. The filter as well as the nosepiece have m48x0. 75 threads.

The sbc2000 is an analogue camera. It connects via bnc to rca cable directly to a TV monitor. Or you can use a frame grabber and connect it to a pc with sharpcap

Yeah, I like it too. It looks like those NASA images, very "scientific" look. 😀

Very nice image, as always Avani!

I have also found this, if you don't mind the waiting.

https://m.aliexpress.com/item/33013757839.html?pid=808_0000_0101&spm=a2g0n.search-amp.list.33013757839&aff_trace_key=&aff_platform=msite&m_page_id=3154amp-UfuZRWmpDhc_EeyQg_4kCg1579027832458&browser_id=2ce6b9f96904439ba06875ab61a4aac1&is_c=Y

If not, look for something like this:

https://www.baader-planetarium.com/en/accessories/adapters-imaging-accessories/2-inch-sc-thread/baader-2"--t-2-nose-piece-and-camera-adapter-(same-as-used-by-sbig)-(t-2-part-16).html

I see that it comes with T2(almost m42) connection and T2 to M48 adapter. So it looks like you need a 2" nose piece (threaded for filters) with either T2(or m42) threads or M48 threads.

Which camera do you have?

I don't think that the glass type matters as much as the overall performance (optical design, polish, F/ratio, etch) .

To put it in other words, how can anyone test if his fpl53 objective, is truly an fpl53??? 🤔

It's been about a year and a half since I took my first photo of the night sky, using my 5" F/10 achromat, my trusted TAL2M mount and an old unmodified Nikon D50. The last picture of this thread was taken with a whole new arsenal. Got an AZEQ5 mount and used the ED80, I already had. A Canon 500D which I modified to full spectrum coupled with the Optolong L-enhance. A lodestar X2c, bought for EEVA, used for guiding, allowed me to go from 30-90sec subs to 300-1800sec subs. Finally, an old laptop with APT, PHD2, Synscan Pro App, made acquisition easy while allowing me to guide, plate solve and dither.

It's been a steep learning curve, but very exciting and great fun.

So this is my shot at the Rosette nebula from this Christmas, 54x300sec, dithered without darks or flats. Stacked on DSS and processed with trial version PI, using pixelmath to produce a synthetic (fake?) SsyntheticHO image.

For the next year( I'm done with buying equipment), my goal will be to learn and master image processing. So, let the games begin!

You mean something like that? 🤣

Second hand market is very helpful to us astronomers (even tempting, I might say - who hasn't grabbed that super bargain just because it was a bargain?). Almost all of my gear is second hand or display items, but then I am not too fussy about that odd dust speck or scratch, as long as the gear delivers. I think 60% of the RRP is pretty decent, but when I sell something bought already second hand, I always give an additional 10-30%, even though I could sell for what it cost me or even more.

Read the title and came in having a picture in my mind of a Takahashi sailing towards the twilight in a viking ship, while the astronomers at the beach shined their laser pointers at it to torch it into eternal glory....

Anyway that's an excellent gesture. I have faced the same dilemma, but I wasn't as brave as you, I just gave it to a student as a very long term loan. Bravo Niallk!

Well, next week over the holidays, I'll have the chance to shoot some subs under the stars, and get some darks and bias with the camera properly shielded from outside light, so we can come to a conclusion as where this anomaly comes from, external light or internal ir light or some strange internal calibration.

Vlaiv I want to thank you again for all the help you're giving me.

2 hours ago, vlaiv said:

DSC261:

 0.018281393 ADU/s

DSC263:

Dark signal is 0.018862519 ADU/s

DSC265:

Dark signal is 0.018966408 ADU/s

DSC269:

Dark signal is 0.019258152 ADU/s

So what you're saying is that if DSC261 (room temp 22°C) has a dark signal value (after bias substruction) of 0.018281393 ADU/s then the expected value of DSC265(outside temp 12°C) would be at least double that or more than 0.036ADU/s (given the temp difference of more than 6°celsius, where noise doubles) instead of 0.019258152 ADU/s?