Weird shaped stars.

[emyliano2000]

8 hours ago, Uranium235 said:

Having said that (regarding the T2), it might not work since the prism would need to intrude further into the light path and may interfere with your imaging chip (ie: leave a shadow).

I couldn't use it anyway. It is hitting the prism.

What I did is made myself some fine tuning rings out of whatever thin plastic I could find around the house. I think I managed to get the 57.5mm with them.

My measurements without my home made rings was approx 55.8mm so I needed an extra 1.7mm. First of all I made 3x 0.3mm rings out of some cottage cheese lids and luckily the plastic cotton buds lid was 0.8mm ? giving me the total of 1.7mm that I needed.

I placed one of the 0.3mm rings between the bayonet adapter and the camera to give me a tight fit. Yey, I dont get any movement anymore.

Then I placed the other 2 0.3mm rings between the eos adapter and the OAG. The work very well, tighten the OAG screws and I get a nice tight fit.

And the 0.8mm home made M48 ring is placed between the mpcc and the OAG and I still have 2.31mm of thread left which is enough to secure the connection and give me a nice thight fit.

I really hope this improv of mine will make the coma dissappear.

Your thoughts please.

[emyliano2000]

If it works all I have to do (I think at least) is imrove my collimation to get the halo centered around the stars and I'm good to go to start learning what exposures and ISO combinations to use for nebulae, galaxies and clusters and then learn how stack them and process them properly. I'm so looking forward for it.

[Uranium235]

Result!

It should be ok since the camera you are using isnt exactly heavyweight (ie: wont deform the plastic spacers). Just make sure you hear the locking pin go "click" when you attach the bayonet adaptor give it a gentle tug in all directions and listen for play - but it sounds like youve got it sorted now.

The proof of the pudding will be in the eating, so all you need to do now is get some clear sky for testing... easier said than done! It should be an improvement over what you had previously since the play has been removed and the spacing increased, I'd be very surprised if it didnt improve the situation.... best of luck mate

 

[emyliano2000]

First of all thanks for all the help and comments.

Second, I just thought of a way of improving my collimation using the dslr without a laptop. I'm thinking of using the smaller grid in live view, defocus a star and try my best using the grid lines to center the secondary reflection to the defocused reflection of the star in the primary and when I get it bang on centered move the defocused star to all the corners in live view to check if everything stays centered.

Would this be a good way to do it without a laptop?

[alacant]

7 hours ago, emyliano2000 said:

to get the halo centered around the stars

Hi. Remember it's the reflections in the coma corrector that are causing this although I'm almost certain that good collimation will help with the coma. Good luck and clear skies for your tests.

[emyliano2000]

2 hours ago, alacant said:

Hi. Remember it's the reflections in the coma corrector that are causing this although I'm almost certain that good collimation will help with the coma. Good luck and clear skies for your tests.

Yes. Im onl thinking that if I get the collimation spot on the halo will be concentric around the stars like in Uranium's second photo where he used a mpcc.

[Uranium235]

FWIW, (and probably a little naughty) I've very rarely collimate under the stars - I think Ive only done it once in the past 5 years, and that was adjustments to the primary only. Once your secondary is set, you really dont need to touch it again unless something drastic changes. Most collimation issues arise from incorrect adjustment of the primary mirror, and in some cases actual movement of the primary from collimation of the telescope in a horizontal position - then moving it to a vertical position when the primary puts its full weight on the bolts/springs.

Actually, that reminds me... I need to replace the primary springs on mine at some point (a common mod for SW newt owners). The same was done with my 130pds by its previous owner. Also, due to the quite heavy imaging train I have, I had to replace the focuser because the stock one on the 200pds suffered from flexure quite badly (I got smeared stars across the whole frame).

Another mod I'm awaiting delivery for is an M55-M48 adaptor so I can convert the Baader focuser to all threaded - similar to what I did with the 130pds where I converted that using an M54-M48 adaptor I built myself. Its all about stiffening and tweaking it until I can flick the camera and the whole telescope tube resonates.

You need to be careful when using live view for an extended period of time before an imaging session, as it heats the sensor up considerably. If you have used it for a few min, give the camera a chance to cool down again before starting the imaging run - also deactivate the rear screen (another heat source) and block up the viewfinder with a bit of tape to keep out stray light. Also, I made a cover for the bottom end of the scope, as light can sometimes leak in around the primary mirror.

[emyliano2000]

12 hours ago, Uranium235 said:

Another mod I'm awaiting delivery for is an M55-M48 adaptor so I can convert the Baader focuser to all threaded - similar to what I did with the 130pds where I converted that using an M54-M48 adaptor I built myself. Its all about stiffening and tweaking it until I can flick the camera and the whole telescope tube resonates.

I've been looking for some kind of adapters to convert my focuser to all threaded too.

So far I came across this Lacerta Thread Adapter for using Baader MPCC with Skywatcher Newtonians (FUFmpcc)  http://www.teleskop-express.de/shop/product_info.php?products_id=5417#cs

I want to somehow connect the FUFmpcc with the Baader mpcc inside it to my TSOAG9EOS and have the correct 57.5mm spacing too.  I have 44mm on my dslr, I know the TSOAG9EOS is 11.4mm to which I have added a 0.3mm spacer ring between the eos adapter and the dslr to have a tight fit. I dont know if the Baader mpcc M48 thread goes past the FUFmpcc adapter or it stops at the end of it.
So all together I would have 55.7mm and I can only afford another 1.8mm of spacing.
I don't wanna use any T2 threaded connections because using those would mean that I would have to raise the prism in the TSOAG9EOS which will cause shading on the sensor.
Is there any chance that I could make the connection I want? Are there any adapters of some sort that would help me make this connection?

I emailed them and I'm waiting for an answer. Hopefully it will be achievable.

Maybe I should've started a thread in the equipment topics.

Emil

[Uranium235]

That adaptor is unsuitable because its the wrong size thread (M56) for SW crayfords - which are in fact M54. The adaptor you are looking for is here:

http://www.teleskop-express.de/shop/product_info.php/info/p203_TS-Optics-M54x1-to-T2-Adapter-fo-Skywatcher-Crayford-focusers.html

However, I do have one but dont use it any more becuase the M54 thread is too short to be considered secure - eventually it would tighten up to a point, then go loose again.... nowhere near secure enough for mounting an expensive CCD. Thats why I eventually had to make my own M54 adaptation.

Actually, ive just read the ad blurb in your link, and it states there is an M54 thread on the adaptor - which conflicts with the image. Its probably best to contact them to clarify what sized thread it is. But... it utilises both the M48 and T2 thread of the corrector (it connects to the adaptor via M48, and the camera connects via the T2) - which I thought was not an option for you due to the OAG.

If you really want a custom made adaptor, FLO have a very handy chap who machines custom made components (its where I got mine from).. excellent service too:

You just need to clearly have your design in mind before you request it so John can give you the best service possible.

However, give your current arrangement a chance to see if it works. You might not need to go down the all threaded route being as its just a DSLR.

[emyliano2000]

9 minutes ago, Uranium235 said:

That adaptor is unsuitable because its the wrong size thread (M56) for SW crayfords - which are in fact M54. The adaptor you are looking for is here:

http://www.teleskop-express.de/shop/product_info.php/info/p203_TS-Optics-M54x1-to-T2-Adapter-fo-Skywatcher-Crayford-focusers.html

However, I do have one but dont use it any more becuase the M54 thread is too short to be considered secure - eventually it would tighten up to a point, then go loose again.... nowhere near secure enough for mounting an expensive CCD. Thats why I eventually had to make my own M54 adaptation.

Actually, ive just read the ad blurb in your link, and it states there is an M54 thread on the adaptor - which conflicts with the image. Its probably best to contact them to clarify what sized thread it is. But... it utilises both the M48 and T2 thread of the corrector (it connects to the adaptor via M48, and the camera connects via the T2) - which I thought was not an option for you due to the OAG.

If you really want a custom made adaptor, FLO have a very handy chap who machines custom made components (its where I got mine from).. excellent service too:

You just need to clearly have your design in mind before you request it so John can give you the best service possible.

However, give your current arrangement a chance to see if it works. You might not need to go down the all threaded route being as its just a DSLR.

Thanks for the advice. I'm a bit of a freak when it comes to getting things right. Keeps me busy all the time

If I knew about it I could've asked John to add the 3rd screw on the compression ring adapter that I got from FLO.

[Uranium235]

lol... I think OCD is a common trait amongst astrophotographers (me included)

 

[emyliano2000]

On Thursday, January 26, 2017 at 10:35, Uranium235 said:

convert the Baader focuser to all threaded

Hi. I can say that I now have some kind of  an all threaded onnection.

I have managed to find a way to keep the OTA collimated for when I attach the dslr. What I've done is tighten the mpcc just enough to keep it permanently in the 2" compression ring focuser adapter and lucky enough my self centering adapters and the hotech laser collimator can be screwed on to the M48 thread of the mpcc. I collimated the OTA with the cheshire inside the self centering adapter screwed to the mpcc and then checked with the laser collimator and it works. 

So now my mirrors are centered to the baader mpcc that will stay inside the focuser and all I have to do when I go out is screw the collimator to do some final checks on the primary before I screw the OAG with the dslr attached to it. I only hope the mpcc won't become loose.

Emil

[alacant]

Hi. Just a heads-up. If you're using the Baader supplied t2 adaptor, you need 55mm from its bottom edge to the camera sensor. If you're attaching directly to the mpcc via m48, 57.5mm. Also remember that the threaded ring on the t2 side that is also supplied is cosmetic; it provides no spacing.

On 27/1/2017 at 00:41, emyliano2000 said:

it utilises both the M48 and T2 thread of the corrector

The corrector has only m48. t2 is provided by a screw in adaptor which adds 2.5mm to the optical length, hence the 55 and 57.5. HTH to get it perfect.

[emyliano2000]

18 minutes ago, alacant said:

Hi. Just a heads-up. If you're using the Baader supplied t2 adaptor, you need 55mm from its bottom edge to the camera sensor. If you're attaching directly to the mpcc via m48, 57.5mm. Also remember that the threaded ring on the t2 side that is also supplied is cosmetic; it provides no spacing.

The corrector has only m48. t2 is provided by a screw in adaptor which adds 2.5mm to the optical length, hence the 55 and 57.5. HTH to get it perfect.

Thanks for the heads up. I didn't know that I must have 57.5mm distance until Uranium235 told me so,  so I made myself some spacing rings to get the correct distance ( you can see the photos on the top of this page).

Im only using the M48 thread of the mpcc.

[emyliano2000]

Quick question. Would a Baader clicklock 2" adapter put the mpcc exactly in the same position every time I take it out and put it back in again? I'm thinking of getting this http://www.teleskop-express.de/shop/product_info.php/language/en/info/p9312_Baader-2--ClickLock-clamp-for-M54x1-Skywatcher-thread.html and this way I wouldn't have to keep the mpcc inside the focuser all the time.

Is it self centering? Would I be able to focus with it?

[Uranium235]

If you are using the stock skywatcher focuser, then no - it wont work (for AP anyway). The clicklock eats up too much focuser travel, it barely had enough travel left on my 200pds with a diamond steeltrack focuser - but its fine for refractors. And in essence, its still a compression ring based solution.