david_taurus83

7 minutes ago, etunar said:

I thought about CCD, but I was a bit intimidated by very long exposure times (20-30min) people tend to use for subs.

I used to shoot 900s Ha subs with my ASI1600 at unity gain so there's not much difference. I found this gave better cleaner results than say 300s subs with higher gain. Personally I prefer to shoot as long a sub as possible than say, lots of short ones. Its a pain to preprocess 1200 x 30s subs, trust me!

Have you considered a KAF8300? If I was in the market now for a mono setup and a sensor of similar size to the ASI1600 I'd gladly snap up one of these old CCD's. Check out Adams pics @tooth_dr

Or see if someone will lend you a known good reducer and try that to see if it is in fact your one thats the problem.

If you've bought new, it needs to go back. Ive not owned one but all the example pics I've seen show good correction with this flattener even with a DSLR. Adding the reducer should certainly not make it worse which is the case here.

I've seen both kinds of aberration either side of optimum.. That chart is useless imo. Your clearly too far away and you still have stars pointing inward.

You need small adjustments. Try it the other way first. 16.5 + 21 + 11 + camera. No filterwheel. See what its like at 55mm.

In the imaging tab you should have all the sub tabs on screen. Platesolve should be one of them as well as Autofocus. If you use CdC to slew to a target initially you can platesolve after and it will centre to target as long as you have the option selected in the platesolve tab.

You can also pause the sequence as opposed to stopping it. Pressing play again will restart the imaging but if you have autofucus configured to a time based lap then it may autofocus depending on how long you've paused for.

Sharpcap won't work with a DSLR and that filter will only be good for white light, sunspots etc. Don't think an Ha filter will benefit as the dedicated solar equipment (Lunt etc) work with extremely narrow bandpasses.

You can get a metre length of M12 threaded bar from B&Q for a few quid. I cut it down with a hacksaw and filed the edges to suit 👍

14 minutes ago, TareqPhoto said:

Yes, it is the Canon one, i bought it very long time in the past when i was in photography, and for that it is a remarkable sharp amazing lens, but now coming to astrophotography i can't tell much as i didn't test it much, only once and didn't process the image since 3-4 months ago, but i see more people favor Samyang or Rokinon, they said that Canon has issues wide open more than Samyang/Rokinon versions, but stopping down to F4 or more then there is no much difference.

Interesting, thanks. I've seen some nice pics on Astrobin with the canon version, even a full frame 6D image with nice round stars to the corners. I picked up a mint example for a little more than a new Samyang. I'm trusting the Canon build quality over the Samyang I suppose and there is the bonus of autofocus and the ability to control focus from APT should the need arise.

On 28/06/2020 at 14:23, TareqPhoto said:

As long i like the lens results but i have the Canon version only and also i have a second camera i am thinking about getting this lens to use 2 cameras, but i really feel that as much i like wide field but i don't like this super wide field always, i mean some targets can be nice like Cygnus targets, but another targets i feel like i really want to stay within 300-600mm range, and i don't know if i should really buy another 135mm lens.

Is it the Canon EF 135mm F2 you already have? How do you find it? I've just bought one.

8 minutes ago, Northernlight said:

By heck these deliveries of mounts are taking some time - mark said they were shipping 4 week ago, so I guessing he must be personally delivering each one on foot lol

 

Have you ordered one? If so I can understand your frustration. If not, then why are you so bothered?

9 minutes ago, dd999 said:

Really great shot! - it certainly adds to the motivation and optimism I have of this little mount.

Is the CEM25P a lot quieter than the AZ GTi?

 

Thanks! That was only 60s shots but it guided steady and recentred with platesolving over a few nights.

The CEM25 is even quiter than the belt driven AZEQ6. If you stand a few metres back you cant even hear it slewing.

That's a cracking image! Did you use any filters?

Out of the 4 goto mounts I've had, EQ5 + Pro, AZEQ6, AZGTi and current CEM25P, the EQ5 was the noisiest. (In contrast, the iOptron is literally whisper quiet) I was concerned when I checked out some YouTube videos of the AZGti but was a bit relieved when I tried it out in person. That said, I did take it apart and added a bit more grease to where I thought it was lacking and smoothed out a rough spot it had when I turned it by hand. I used mine in EQ mode and got decent results at 350mm focal length. Guided 5 minute subs were easily achievable with good polar alignment and balancing. Dec backlash was a bit of a pain but if guided in North or South only it was fine. Average 1.5" RMS. And that was with 5kg of kit with 2kg of counterweight. Very capable little mount. Best picture I've took (imo) was on that mount.

It appears that actual port is USB3 traffic only. The others are backwards compatible with with USB2.

2 hours ago, Wyvernp said:

Morning,

I'd love to get some advice from anyone who uses the GT81 and Flat6aiii, what are you using as your backfocus distance? I've read online anywhere between 55, 60.1 and 62.1 and am struggling to get my corner stars shapes to be anything but streaks.

any advice would be appreciated.

Wyvern

According to this you should be somewhere between 5.1 to 7.1mm on the adjustment, assuming you have 55mm from the shoulder. Pretty much what you've said above. I spent many an hour trying to "perfect" my spacing. Try too close at 55mm with the ring closed and work out from there. My corners were never as bad as yours though.

37 minutes ago, michael8554 said:

Sorry, I've only got a sketch of that chart.

If it's too close, the stars point to the corners.

If it's too far, the stars form "star trails", as if Polaris was in the centre of the image.

But a past discussion implied the Too Far and Too Close labels were reversed !

Flatteners for mirrored scopes and for refractor scopes  require optics with opposite correction ?

Try a gross offset to check which is true for your setup.

Michael

I had a thread about this and I may have said this. In fact, I have seen both kind of distortion either side of optimum distance. I think at the time I was investigating whether filters in the image train needed to add or minus an amount of back focus.

I found the quoted distance on my old WOGT71 and Flat6A II to be as best as I could get.

Your centre stars look out of focus BTW and this can exaggerate the effect at the corners.

Am I right in thinking this issue is not possible with a transformer type linear power supply?

On 20/06/2020 at 16:11, TerryMcK said:

Which way around do you have the filter?

The IDAS D2 is directional meaning that the male threaded side goes to the sensor and the female threaded side goes to the sky. I had to buy an adaptor that enabled me to turn mine around in one of my scopes.

You can turn the filter around in its cell by carefully unscrewing the retaining ring.

3 minutes ago, knobby said:

If you get a good one it really is a cracking mount, love your set up, very similar to mine, I've managed 500 seconds too but more like 1.8 arc secs.

I actually sold it a while back and got a CEM25P so I could use my 102mm scope for imaging again. Mine was really good on RA but had a lot of Dec backlash. Still guided fine. Worked best to guide in North/South only and dither in RA.

5 minutes ago, dd999 said:

Impressive - do you find the Manfrotto 055 sturdy enough under the weight? Assume it's the xprob?

I'm just about to buy steel tripod legs - https://www.rothervalleyoptics.co.uk/skywatcher-stainless-steel-tripod-with-38-thread.html - but would prefer something a little more portable

Yes XPROB. I used to spread the legs out another click and have the setup low to the ground. Was very stable. As is in the pic, it was a little forward heavy towards the weights as the wedge is inverted due to how you have to mount the AZGTi.

It shouldn't be that loose. You can tighten the flat brass screws a tiny bit to give it a bit more friction. Both my Altair EDR scopes have the same type of focuser. What I dont like about mine is that self centering locking collar. It's far too stiff to both lock and unlock and I have to grip the focuser firmly to stop it rotating. If I wasnt using a threaded connection for imaging and I observed more often I'd ditch it and buy a ClickLock.

Kit about 5kg and 2kg counterweight. I used this setup for 5 minute guided exposures. The best guiding I got out of it was around 1.2" RMS with 1.5" being more the norm.

Just get an intervalometer and your away. 50mm is pretty wide field so you should be able to get some nice shots of Cygnus in a few weeks once we're past solstice and it rises higher. Try 60s exposures first at around F4. Wide open with that lens makes the edges distorted but if your not bothered 1.8 will make it pretty fast!

On 11/06/2020 at 22:10, RodAstro said:

Excellent

I got my best picture yet using the Scouts Quark unit on tuesday.

Cheers Rod

That's great! Is this with the Solar Scout as is or have you somehow removed the Ha unit and mounted to a different scope?