Jamgood

Not had much of a chance to do anything throughout August here. Constant clouds.

Last night was a little clearer that of late but the Moon was high and washing everything out so I went with that and figured I can use it for practice and editing, etc. I only took and stacked 20 shots. Next time I'll try without my CLS filter. It was a struggle to remove all the green.

A little over processed I think but I still quite like it.

Have you installed the ASCOM drivers and set up EQMOD with the relevant settings?

Not as good as the pictures on here but this is my first real attempt at gathering data and getting my first real shot. (I've spent some time playing around taking a few shots here and there, testing everything out.)

This crop is the result of about 1hr 34m of data shot at ISO 1600, 40s exposures from a Bortle 8 UK garden. I've got a lot to learn about about post processing as it's all very new to me. There's a lot of red in the background that I'm struggling to get rid of. More reading of tutorials and learning to be done.

I'm pretty happy with this for a first shot though.

Edit* Had another go at processing the image and try and remove some of the horrible red.

On 04/08/2020 at 20:57, merlin100 said:

An old, but still relevant guide to observing in light polluted areas...

https://www.youtube.com/watch?v=pb69G_8M7TY

Brilliant. I miss Sir Patrick. I watched him all through my childhood and into adulthood. The Sky At Night isn't the same without him. Still good though.

My first shot of the Moon with the 130PDS. I was just playing around with settings and trying things out as this is all new to me as yet. 

I have the same scope and had similar problems when I first started with it. (Still not 100% perfect but getting closer.) My star tests looked like yours. Are you sure it is collimated? Are you using a laser collimator and is that collimated? My laser wasn't, it was terribly out and caused me more trouble. I got a cheshire eyepiece and have had more success with that with a little help from @Pixies in this thread >>> 

 Check your laser, if you haven't already. 

Regarding tilt with the camera adaptor which is due to the 2 grub screws pushing the connection in one direction or another. I found a layer of masking tape around the edge of it makes it fit nice and snug and reduces much of the tilt. Maybe you could try something similar?

Others with more knowledge will be along to help you I'm sure. Good luck! 👍

I'm new to this myself with the same scope. Firstly I'd say, don't touch the secondary mirror unless you're absolutely sure you have to. I had no choice but to adjust mine and it was a nightmare as a newbie.

Is your laser collimated? Mine was off by a long way. Watch this.....

Others will be along with better advice soon.

A quick update. I got the collimation much closer to where it needs to be. Not perfect but much better than it was. I managed to get out and try it last night for the first time. 

I'm going to speak to someone at FLO next week and get a proper Collimtor Cap, a fitting to get the Cheshire right into the tube and a Coma Corrector. I'm confident enough now that if I can see what I'm doing, I'll be able to get it as near as dammit!

I'll check it on Saturday night, weather permitting. It's supposedly going to be clear. 👍

30 minutes ago, Pixies said:

One thing to consider, regarding how the collimation changes if you move the scope. Make sure the spider vanes are tight. After I had replaced my secondary, I found collimation would change when I raised or lowered the scope. After tightening them up, that was fixed. 

I have checked them and they are tight. Measured them also and from what I can see they are equal.

I got one from FLO. It doesn't say the size but I figured it would slot into one of my attachments better than it does. I might see if FLO will let me return it as it's pretty useless at that distance.

https://www.firstlightoptics.com/other-collimation-tools/astro-essentials-cheshire-collimating-eyepiece.html

@PixiesLike I said earlier. Practically useless. 

6 minutes ago, Pixies said:

How big is the Cheshire?

 

Huge. Sticks out of the focus about 6" - I expected to be able to slide it in to the focuser but I don't have a correct fitting.

28 minutes ago, alacant said:

Point the telescope at the sky or a bright surface with the 45° surface of the sight tube orientated so it is eveny illuminated. Take a shot through it with your 'phone and post it here.

 

I'll point it at the sky tomorrow after work. The lights are crap in my house. Migraine proof for the wife.

20 minutes ago, Pixies said:

I notice how you can't see the outer edge of the primary any more?

I could with the collimator cap but not with the Cheshire. The photo below is how it looked before I adjusted the primary slightly. Is it because of the focuser tilt, maybe?

37 minutes ago, Pixies said:

Hi,

Sorry it hasn't been a success, today. Yesterday looked so positive!

It's odd how that flat spot doesn't appear in the silhouette. The secondary mirror is quite large though, so as long as you can see the whole of the primary in it, that shouldn't have an effect. Can you see whether the whole of the primary is visible over the whole range of the focuser?

Alacant says - you can see the end of the focuser tube when it is fully in. As long as you don't need to get in that position when focussed, that shouldn't matter. Mine is similar.

Try A's suggestion and get it as close to collimated as you can, then move it to various extremes on the mount and see whether it stays in collimation.

It might be worth putting a call-to-arms for the 130PDS owners in the general equipment forum, with an obvious title, like: "130-PDS owners - help!" and direct them to the end of this thread.  Someone might have seen this issue before.

Have you spoken to the supplier?

 

P

It does have to be zoomed in quite a way for focus to be achieved. (Usually making PacMan shaped stars) The focuser tube does protrude and that I expected from what I'd read about the scope before buying. I know a lot of people cut the tube down or move the primary up the tube, losing focal length but not having to butcher the focal tube. From what I read, there's a certain Coma Corrector that has enough back focus to omit doing either of those. That's what I planned on getting.

I used the phrase D Shaped stars but they were more like arrows. Starting from the outside, pointing inwards towards the centre. Like they are out of focus but the centre star is bang on. Almost like drift but all drifting different directions.

When I insert the camera to the focus, the two grubs screws force the attachment to an angle. either up or sideways. So what I've done tonight is force the Cheshire in the same direction and (hopefully) collimated it. Out of interest and frustration. I spent an hour or so on the laser collimator, took it to bits, straightened the bent spring that is inside and manage to collimate that so it was almost bang on straight. I did the same with the laser as I did the Cheshire and forced it to look upwards via the two grub screws and that was bang on without me touch anything. Right in the centre of the primary and back into the laser. So that looks promising. I didn't try moving the scope to different extremes as I forgot at the time. 

Not sure if it will work or not but I'll have look when it's clear. I haven't spoken to the supplier yet. If it doesn't work this time I might just get a replacement and see how that goes. I might get lucky with the next one.

This is how things look at the minute. It's hard to photograph down the Cheshire.

Everytime I get this part to a near perfect circle I end up with a flat edge. (Top right quarter) Any adjustment from there and I seem to lose the circle and go round in circles, literally.

I'll start from scratch again and see if I can get it anywhere near. 

1 hour ago, alacant said:

Hi

It maybe that the primary mirror is moving rather than the focuser. Or the secondary is loose or missing a spring. Maybe the primary adjusting screws have come off the end of their thread... Loadsa stuff it could be e.g. I had to fix my primary to the cell with silicone 'glue' before it would hold collimation.

As it is, it will work, but you'll lose faint detail and the stars won't look good.

Assuming you've got the secondary more or less in the centre of the tube, insert the Cheshire with the focuser at the same position as where your camera/eyepiece focuses. This way, you'll collimate out any the tilt. Adjusting the secondary only, get the Cheshire cross hairs on the primary donut first. Or at least somewhere near. Then leave it. Now adjust the primary until it's concentric. Now move the telescope. Does the collimation stay?

If you want it for astrophotography, best to dismantle and reassemble, especially the 1º mirror cell. The focuser can be adjusted too but remember, at this price point, you're gonna have to do some work to get it up to the necessary standard.

Before you give up - and remember that it's always best to leave stuff like this 'till the next day- be sure to read the collimation myths. It's a lot easier than you think:) Below, I've put the current state of play.

Good luck and do tell us when (sic) you have it fixed.

Cheers, good luck and HTH.

Part of the problem, as I see it, is when you put the Cheshire in the focuser, there are only 2 locking nuts and they push the cheshire off to an angle. Does the same with a camera but the angle, each time, is never consistent. So what looks lined up changes when you go back to it.

The Cheshire being so far away from the secondary doesn't help me at all. Looking through the tiny hole, everything is black. (I can't put the Cheshire in the focuser tube)

So with the above I'm having to rely on taking a photo with my phone,  (god knows how reliable that is) email it to myself, check with the crosshairs in the collimation app. Rinse and repeat. 

What was looking all line up yesterday didn't work. I did some quick snaps of stars in a gap in the clouds last night. Couldn't get any focus at all. Sharpest was blurry and everything else was D shaped. I'm not sure if that's to do with the secondary mirror as when it is as close to circular as I can get it, it has a flat edge. 

The hardest part is that I'm not really sure what I'm doing. I'm learning as I go but no way would I be removing mirrors and stuff like you're saying. That's a sure fire way of making it completely destroyed. I'm not that handy.

I think the thing is defective.

I'm ready to give up on this and send it back, try my luck with something else. The Cheshire is useless as it sticks out too far the mirror to be able to see to align anything. I thought I'd be able to slot it in the tube further but SkyWatcher haven't supplied anything that will work that way.

I keep spending money trying to fix this thing and I haven't had a single minute of enjoyment yet, just stress.

I've messed it up completely today but when I put the Cheshire in, it looks different everytime because the focuser is renowned to be rubbish.

Got the Cheshire today. I wasn't far off with my homemade cap. I think this tool is going to make it a lot easier though. A little tweaking here and then on to the primary.

13 minutes ago, Pixies said:

No problem! It was good to get my understanding of it down on 'paper'. I made some mistakes when I got my new scope and nearly mucked things up well-and-truly!

 

Geez! At least you managed to sort it out.  I don't think I'd know where to begin on your problem.  That would've been a total nightmare for me.  Interesting to see you mention Bobs Knobs in that thread. I could have used some of them over the last two days instead of messing around with a tiny allen key. One day I'll upgrade them

15 minutes ago, Pixies said:

This offset is only there for fast scopes. Ones with longer focal lengths don't have them and their secondary silhouettes are central.

That was the bit that confused me the most. I had read that fast scopes have an offset but didn't really know what that mean't (lots of pictures show lots of things) and as mine from the factory was so far out, I thought that was the offset and along I went merrily confused.

It'll be interesting to see what it looks like through the Cheshire when that arrives. If nothing else, I feel more comfortable adjusting things now and have more of an understanding of how it all works. You explained it better than any guide I read or video I watched. They basically say "get a laser and you're done". I did and I was! Haha.

Thank you for your time and patience Pixies. I'll be eternally grateful and hopefully, someone else along the way will find this thread and learn something, as I did. Can't test the scope tonight as it's cloudy but I'll update when I can and when the Cheshire arrives.

Now......Guinness. Cheers!

Right I get it now. The doughnut needs to be in the centre, not the bigger black circle, which is the shadow of the secondary.

I seriously just had a "Duh" moment! I've been trying to align all the circles in the centre. I did say at the beginning I needed help.

I thought the all had to be concentric circles? Equally distance etc.