Skipper Billy

A pal of mine is selling an upgraded model of the scope that @alacant linked to - cooling fans, ES flattener the whole shooting match. It was mine from new so I can vouch for it - its completely flocked and all the screws have been changed for stainless steel etc - its a cracker. I don't know where you are located but the scope is in Glasgow. I can put you in touch with him (and translate for you 😉 ) if you wish.

That sounds like just what I need - roll on the Summer release date !!!

If I was Lucas Mesu I would be talking to copyright/patent lawyers right now........

There is a strong ethos in this group of helping each other and saying thank you afterwards.

An expectation of mind reading and lack of common manners is often counterproductive long term.

Just saying.

Uuuurrgghhh. !

It looks like your camera isnt working properly.

Have you installed the correct drivers for it? 

Have a read at the second document down on this page - https://www.davidbanksastro.com/how-to

If you follow it step by step you should end up with good guiding.

PM sent but there is clearly an issue with star shapes.

2 minutes ago, oymd said:

But isn't this setup:

11mm + 21mm + 16.5mm = 48.5mm?

Shouldn't it be 55mm?

The sensor is 6.5mm recessed - makes it 55mm - spot on!

The setup as you have it now will work just fine as long as you can achieve focus??  Personally I would add another spacer into the mix so the focuser doesn't have to be racked out so far which can cause droop/wobble.

Back to your flattener. It looks like you probably have the parts needed to get fairly close to 55mm from the flattener to the sensor. The attached drawing might help - from the parts list you posted it looks like you can get the camera end down to T2 size as well as the flattener - then just work out what you need in terms of T2 extension rings to get the correct distance or incorporate an adjustable Baader extension as Tooth Dr suggested which makes life easier.

There is a great selection of extensions here - https://www.firstlightoptics.com/adapters.html  T2 is far and away the most common size.

Dont be tempted to screw a T2 fitting onto M42 fitting - they are damn close but slightly different thread pitches - if you force them they will both be damaged.

The attached drawing gives you the distance that the sensor is rebated into the camera body to give you a start.

Once you have it all screwed together and the distance is spot on its a good idea to take it apart again and lightly smear the threads with boot polish to make sure they dont become cold welded together in case you ever want to take it apart again.

Good luck and welcome to a drawer full of redundant spacers!! 😉 

OK - both the unprocessed single light and the single dark both clearly show heavy banding.

This suggests to me that there is an issue with the camera.

I will dip out now as I know nothing about DSLR's and I have heard of 'banding scripts' etc that may cure the problem but I am well outside my (very shallow) knowledge pool 😉 

It looks like Adam and I are applying the process to different cameras hence the different numbers but the principle is the same. You have to get 55mm between the flattener and the sensor.

It will also give you a screw together system that eliminates any slop or droop in the connections.

Cross posted - sorry Adam.

You will need spacers to connect the threads on the rear of the flattener to the front of your camera and at the same time achieving a spacing of 55mm from the aft end of the flattener to the sensor.

I dont possess the same camera or flattener but I think the camera comes with an adapter that is M54 to M48 and adds 21mm to the spacing and the sensor is reccesed by 17.5mm - this totals 38.5mm so you will need an M48 - M48 extension ring of 55mm - 38.5mm = 16.5mm to give the correct spacing.

https://www.firstlightoptics.com/adapters/astro-essentials-m48-extension-tube-set.html includes a 15mm but if you shop around you will find the 15mm on its own.

Then a set of thin spacers https://www.firstlightoptics.com/adapters/Baader_M48_adjustment_rings.html will get you to 55mm and give a bit of wiggle room for fine tuning.

Hope that helps.

@Mr niall  Can we go back to basics.  Can you post a single sub straight from the camera - no processing of any kind. Then we can see if the banding is present on a single sub ie is the problem the camera or the processing. Then we can move forwards. I am no expert but will gladly help if I can.

When I am imaging close to the horizon and/or in poor seeing conditions I get up to 7 sec exposure on my guide cam. In good conditions I usually run 3 sec.

Back ground extraction shows the true extent of the strange banding and the vignetting.

The banding is the first thing I would try to address - dodgy USB lead maybe ??

What's the problem ??? 

I use an Intel NUC - i5 with 16gb Ram on the scope - its linked to an indoor PC via Remote Desktop.

I does everything I can throw at it inc rough processing in Pixinsight whilst imaging!

Takes up very little room and allows getting rid of all the pesky cables - bar one - power!

Some photos here - https://www.davidbanksastro.com/equipment

Looks like Atlas may be falling apart??

If you want to see my humble efforts mine is here just to save you searching!

https://www.davidbanksastro.com/micro-observatory

Just found this info on CN - might be useful?

To adjust it properly, you must first remove the cover from the rack and pinion. by unscrewing the small flat chrome screw on the bottom of the focuser (use a bent paper clip in the shape of a U or a pair of sharp tipped tweezers as a spanner wrench to loosen that chrome screw. Then remove the cover over the rack gears and LOOSEN the two screws that tighten the tension clearance on the gears ( you will need a small #3 Phillips head screw driver, get the clearance loose and sloppy, but still able to turn the focuser knobs and move the focuser in and out.

(WHY? The three screws along the top of the focuser adjust the play in the focuser tube by pressing the tube against the bottom of the focuser housing, if you do not loosen the pinion gear shaft, you are just pressing the focuser tube against the pinion gear, not the bottom of the focuser housing).

NOW adjust the three small allen hex screws along the top of the focuser (use a tiny drop of acetone to loosen the glue holding them) they take a 1.5mm allen wrench. Adjust the three screws while turning the focuser knob in and out until all slop in the focuser tube is removed and the tube still slides in and out without binding. (Start with the middle screw, then the front screw, then back screw).
Now go back and tighten the two phillips screws on the rack until you do not feel any slop when reversing direction of the focuser knob AND the rack moves smoothly without binding, (DO not over tighten this adjustment as it will cause rough movement and binding of the gears, also slop will only be felt as looseness or back lash in the gears and not hurt the scope movement, so a little loose is beter than too tight).
Replace the cover and screw and you are done.

EDIT: A few more points, the glue used to secure the three screws along the top of the focuser will re-dry in about an hour (if you don't use too much acetone to loosen them, if the stay loose? just use a drop of clear nail polish to re-secure them.
Let me know how this works for you? 
Rex

Refractor for me - no messing about collimating and no diffraction spikes. Petzval design - no messing about with spacing between scope and sensor.

Ah - I see.

David.

I found this to be extremely useful 

https://www.lightvortexastronomy.com/tutorial-setting-up-and-using-astrotortilla-for-plate-solving.html

15 minutes ago, gorann said:

Yes, I think they are both on 3 seconds, but when I have been playing around with it (from 1.5 to 5 s) it does not seem to make much of a difference. And thanks, I will now try to seal off any possibilities of light leakage!

If changing the exp time doesnt make much difference then it would suggest that its not a seeing related problem ?? 

Could you easily attach your finder guider to the longer scope? That will tell you whether or not its your OAG or not?