HaleBopp2007

I'll try to shoot the comet tomorrow. The situation is challenging thanks to the twilight, so I'll just hope for the best and maybe I'll get a nice shot

Well, I can now confirm that my scope worked flawlesly now! It did the meridian flip (which made a couple of exposures a bit wonky), but the rest came in wonderfully! Even being west heavy helped the issue, too! Thank you all for your help, I'll make sure to send the image as soon as I finish the project. I wish you clear skies!

Okay, confirming half-victory over that pesky backlash! I am however getting slightly elongated stars (just a few pixels) while the field is completely still... I've checked that the  alignment corresponds to the RA axis, implying it's a declination error (probably polar alignment mistake) so maybe I have to apply more aggressive guiding, since I don't think making the mount even more east-heavy is something that improves dec errors. The issue is however mostly solved, I just need to polish the procedure

Update! I'm photographing NGC 7000 and so far it looks like your tips did the job! I still have to try with other positions, but so far it looks very promising. Thank you all so much for helping! I really needed that!

Apologies for taking some time. Last night was oddly hazy, humid and foggy so I didn't try anything for the sake of my optics. Tonight looks much more promising, however. I'll take a shot and see if the mount issues are still there after I use east-heavy weighting and guiding.

Faur enough. I think that the dec issues are because I made a slightly imprecise polar alignment, so that is fixable. If that only leaves me with RA wobble, I think east-heavy weighting and guiding could solve the issue. I'll see if I can finally stop this mess tonight, and increase my already existing excitement (discovered new asiair tools). Final updates in the next 12h

Just made this video with my data of M8 from a bortle 4 sky, it shows the same zig zag pattern. I'll try to check if the east-heavy weighting solves this tonight

I did try that a couple of times but the jump was (and still is) so massive (sometimes around an arcmin)  and sudden that it was impossible to fix with guiding, even when the guidescope's focal length was of more than half of my main scope's focal

Hm I don't fully get every concept. I do understand the 0-0 example, since it has happened to me several times, like two brighter replicas of the same star with a bridge between them. But you're saying that if I leave the eastern part slightly heavier, that bridge of light will dissappear? Sorry if I'm getting too confusing, but I'm trying to grasp as much info as I can to get this 100% straight

39 minutes ago, ollypenrice said:

The Dec motor is active in autoguiding since it is used to correct errors in Dec. These occur even in a perfectly accurate mount, perfectly polar aligned. (The apparent position of stars moves with atmospheric diffraction as the altitude of the object varies.) The dec axis can also introduce errors by having backlash. Backlash can also affect the RA axis and can be made worse by perfect balance. It is best to be heavy on the east so that the imbalance leaves the payload resting on the pushing side of the mesh. Dec backlash can be addressed by deliberately small polar misalignment and the disabling of the guiding direction not needed to correct this error. (Obviously it is best to correct the mount mechanically, however.)

The focuser is another popular cause of image shift and the hardware holding the gear into the drawtube is another. Screw fit beats push-and-locknut.  Exceptionally, chips can also be lose in cameras.

My own hunch is that you have more than one source of backlash but mostly RA. The most important thing to do is identify the RA and Dec axes on the trailed images.  Could you post a star trailed image with the axes identified?

Olly

 

Sorry if it's a silly question but, you mean that the telescope is more stable when the eastermost part is slightly heavier? Like- gaining sturdiness? That could be a solution! I will try as soon as I get my equiment back in action, and I'll also send the footage with the axis identified by tomorrow, but hopefully the east imbalance will do the job

I wasn't guiding in that image. Only the RA motors were working

Nonetheless the exposures of the comet are only stretched and cropped after editing (I have the original video with no cropping and it shows the same effect as well). 

Nonetheless, if it IS an error in declination that definitely discards that it's an error of the motor, since it's not active while tracking. It can't be a balance error either since I've made sure the scope could be easily leveled by adding a longer dovetail. So... I can only come up with mount stress, which isn't really solvable unless I get a newer, sturdier mount

Well, I can do that tomorrow since I don't have my ASIAIR currently... I'll look and see if I have any more exposures, but I think I'll have to wait until tomorrow, with my most recent project which was forunately saved by transparent dark skies. I'll see if I can create a time-lapse asap

Actually I looked for it manually and activated sideral tracking speed, so the comet is not really an important factor this time, since I let it skid through the field, and the timelapse itself is rather short too, with a span of around 40 minutes, explaining that the comet doesn't move much

Oh I do have a time lapse of comet ZTF!

And, yeah it does show that "zig zag" movement

Since I completed my first rig (Esprit 80ED, ZWO ASI533MC, NEQ5) I've suffered from erratic star movement in around 30 to 40% of my exposures, making me scrap a lot of my data. I've put the blame on my mount all this time, but judging by how the wind didn't affect the issue (even at very calm wind speeds I still got the issue), I'm starting to have my doubts. Mount related issues shouldn't be related to these kinds of movements, specially at a quite decent FOV of 1.5° by 1.5°... I have several examples of these movements, and even though these are low resolution versions of the actual exposures, you can perfectly notice that the star trail isn't straight, but it has an irregular trail. Can anyone confirm whether this is either related to my mount as I expected or something else? 

I am going to get that camera very soon, so I decided to check the manual file. I just cannot understand all of those graphs, the gain, gamma... It's just a mess of words and graphs. This is my first time with a CCD camera, so... could someone please explain these?

We have the ion tail, everyone! (image by Michael Jager) 

Alright, thank you both!

Oh no, I mean the standard EQ5 with its GOTO kit

Hello, I'm planing on buying the ASIAIR Pro. How do I connect it to the NEQ5 GOTO system?

On 20/09/2021 at 21:18, Paul M said:

I had a promising sky last night once the clouds dissapeared. But then the dew point became a problem. the sky was particularly milky and my view to the low NE sky was directly through the glow of industrial LED flood lights! Elevation was between 10 and 13 deg.

The gradient on the subs was, I thought so extreme that I'd wasted my time. Anyway, I got 7 x 180 sec with my 10" Newt and ASI071 Camera + Optolong L-Pro filter. Binned 3x3. Only calibration is flats.

Stacked, stretched, background equalised and comet annotation all done with ASTAP. 

I know it don't look pretty but I'm astounded by just what ASTAP pulled out of this data.!

That's a good one! Now the first visual reports are coming, and the comet seems to have reached the 12th magnitude... If this trend continues we could get a decent naked eye spectacle for some days

Right, thanks for the advice! Will wait until the next new moon after I get some nights with it

It's a pity this scope has this... I have lots of fun imaging with it

There's been some recent observations... In the facebook 'Comet Watch' group, Michael Jager is estimating the comet to be mag. 13.5! It has a 4 arcmin long fan tail with a bright and condensed coma:

Also, this image is from a couple of days before, as haze worsened the most recent one (the mag 13.5 report) 

I was planning on doing it tomorrow (I was going for the double perseus cluster) without it for a while, will tell the results on monday.

Also, I think I explained myself badly. The 'fan' rotates but along the actual field. So If it points for example to the trapecium in M42, it still points there when I rotate the flattener, will edit the main post