Robindonne

Oh great.   My first helpful post🙏🏼   Thx

I found the 60d and 600d and maybe lots of other models all offered for the same price.  I went for the 60d.  A step up as mentioned but also a good weathersealed body

So you mean in the “mainCam” menu you dont see your dslr? Are you sure the battery is full and the camera are “on”?   try another Cable?    I have almost the same setup and had never problems. Only sometimes when i forget to turn the dslr on, it indeed shows a greyed out asi120. And thats grey because its already dedicated as my guidecam.   
 

Of course you also tried all the usb ports on the asiair? Cameras in bulb mode etc...

1 minute ago, Edward Dewolf said:

I should have have maybe mentioned that I use my main scope for astrophotography with a guide scope.  Would that change much?  Would a red dot finder be good enough then?

Well i can only tell what i prefer, but im not the most experienced one.  I do know that each night starts with a 3 star alignment where i use the rdf to adjust the mount roughly (if needed) and for finetuning the alignment i use the crosshairs on my camera(asiair) app instead of the crosshairs in the finderscope.  But sometimes, when circumstances just wont let you do photography,  a (raci)finderscope is a welcome tool.  

Also prefer the red dot finder.  And especially one that can be adjusted in brightness.  I think it depands on what you end up doing that night.  My first nights of only visual, and doing a 3 star alignment, it was -rdf-finderscope-mainscope. Once aligned i only use the rdf.  
 Now when beginning to move to ap, the finderscope is never with me anymore. The start procedure is 3 star alignment using rdf and screen of the camera(app) instead of the finderscope.  

Must say that im glad to have a raci next to my standard finder.  I think a must-have part of the standard arsenal.

Oh and when you have to buy a rdf, i would suggest one that has the small bracket with one screw.  The rdf has an arc shaped slot in it and it seems to always find it previous position. And the bracket isn’t like a bay window sized normal bracket

Grab and pull!!! (And an twist in the mean time).  
you can just screw it out and examine it

Okay.  Wel i hope it is.   The night before, when assembling the sct ring to the oag, i noticed how tough the reducer was screwed out of the oag adapter(sct-m48).   It seemed that the rotation mechanism of that oag putted some real force on the adapter, so much that unscrewing wasn’t possible.   A good thing of course if you’re worried of things getting loose, but the tension was the first thing that came up my mind.  So reflection is the possible cause of this crab-shaped star?    Ill try tonight without the oag prism.  See if it works.   Thanks 

It’s gone after removing the reducer.  I

First night out after a cloudy week.  And i did change some adapters in the mean time to get to the required backfocus of my c8+reducer.   But what can this be?   
tension on the reducer?

Im all ears for this experiment!!

On 07/06/2020 at 21:40, Starflyer said:

Complicated I know, but worth getting it right and only spending the money once.

Can you give me some advice from where i have to start measuring the 105 mm backfocus in this setup?

Edit.  I did find some info on measuring and from what point to start.  Although it seems not very logical to start measuring from the end of the sc thread (it is like 10 mm behind the glass of the reducer??). I had a 10 mm extension ring somewhere laying to keep some paper in place but it suddenly had a purpose for reaching that 105 mm backfocus.  The total package from the glass of the reducer is now around the 105 mm: 66 mm (extensionring, oag, T-mount) and 45 mm inside the dslr.
I couldn’t use the whole thread on the reducer, only 6 mm. 

On 07/06/2020 at 21:40, Starflyer said:

Once you have a working set up with 55mm backfocus you can simply swap the coma corrector for the flattener / reducer to use the camera on a different scope.

That was indeed my initial plan.  To build one camera/guidecam/oag assembly to swap between scopes.  Again warned by members here and again have to admit they were right.  I think it is going to be a seperate oag for the newtonian.  
I bought the oags secondhand and didnt pay more then 100,- for the two, so no bigg losses till now. Both TS, a 16 mm and a thicker rotatable one that’s on my c8 and stays there i hope(while typing starting to think of the backfocus of that f/6.3 reducer on the c8🙄).  

If it was more standard i would definitely build a swappable camera/guider set.  But with the different connections needed between the correctors i probably end up having at least two configurations.  
 

edit: the backfocus seems to be 105 mm so i’m safe for the c8/reducer/ultra thick oag/dslr config🙏🏼

I bought a 16 mm oag, a flattener, and again an even thicker oag before i asked questions on this forum.  I realize now that  it wasn’t the smartest move.   Didn’t even know the importance of the correct backfocus.  So im back to the drawingboard!   Although not really experienced with this oag issue, i do think moving the prism in and out the path of the main sensor doesn’t get the guidecam in focus.  In my case its the t-mount for the guidecam that has to be adjusted closer Or further from the prism.  The prism just stays in place.   I needed 1 mm extra to get the guidecam in focus so just used a small washer between the guidecam t-thread connection 

1 minute ago, Alien 13 said:

My scope was brand new and had no felt etc inside the dust cap, I bought some very thin sticky felt for it cut into 3 small pieces..

Alan

Thx.  

5 hours ago, Alien 13 said:

I recognize that scope/hand/Jedi gown  its me. I use sticky backed felt from a craft shop in all instances where I need a padded spacer like camera lens foot rings, protective caps etc.

Alan

Oh great.  I hoped this photo triggered you again🙂.   So you mean you also had no tape inside the cap? Was it original sold without?  Ill will try the felt option also.   But it must be very thin.  Otherwise it just rolls up when putting on the cap.  

1 hour ago, John said:

Yes, I've done that.

It looks like a William Optics scope, or a clone of one.

 

Yes it’s the ali express zenithmoon 71😬

Ok.  At least good to know its just not available special for this.  Then i can start searching some tapes meant for other purposes.  Thx

2 minutes ago, John said:

There is no special tape sold for this purpose. I don't know what scope the dust cap is from but they are all different so it is a case of finding something suitable in a DIY store that give you the fit that you want over the end of the scope.

3 pieces of tape will give a more even fit than 2.

 

Its for this scope.  And i dont know whats original inside the cap because I bought it secondhand.  Have another same type scope with the same cap but other color and size.  This cap has a soft almost like velcro tape in it.  But the space between cap and the scope is so small.   Its almost tight with these 2 pieces of tape seen on the photo.  

Oh maybe good idea to tru that silk ribbon.   I hoped some manufacturer made a special tape for these problems.  Also camera/photography related problems i guess.  Just dont know for what to google?!   I am going to try find that silk ribbon.  Thx

Don’t know if dustcap is the correct translation but i mean the frontcap on the telescope.  The big one thats very important to remove when looking through it.  One of mine is a bit loose.  And the aluminium cap is, besides the noise from being loose, also coming of very easy.   I see 2 pieces of thin tape but the third, to keep it tight, is missing. Does the astro community sell tape especially for these situation?  I tried all sort of cotton tapes but non of them worked well.  Ended up using a thin piece of band aid.  But even that was too thick and had let a bit of the glue come out on the outside.  So the cap was fixed more then i hoped with this tape

Oke while being also starting i came across this one.  The ring is 1,5 mm so it leaves even room for a 9 mm oag in the whole setup.  I was struggling a bit with all these accesoires and oag-configurations, but got a lot of help here!   Only thing is the es mpcc from the added picture is only a flattener and no reducer.  Don’t  know if the combined one is also available but this one came for sale by a person who bought the wrong flattener.

ps.  While owning the mpcc and knowing the rare 1,5 mm thickness of the t-ring I recognized the ring on the covid-app.  It looks like it has the same thickness.  So worth a try.  I ordered one to find out

1 hour ago, Bobby1970 said:

Is this with ASIAIR ??

 

Cant wait to get mine. 🙂

Yes.  And im not sure if its the most accurate.  But it guides also.  So why spend 300+€ on a polemaster when the complete asiair does it also.   I did notice when manual polaraligned, and really spend time on doing a accurate job, the asiair let me do some adjustments afterwards.  And after that second method with the asiair, the polaralignment in the synscan menu asked again for adjustment!

Lol sorry for all these burning questions!   No I didn’t try it.  But i sure will.  My question about what happens when not using the adviced backfocus was kind of related to that try.  Because when i use the “es” mpcc im far away from that 55 mm backfocus.   Dont have a guidescope so have to stick my oag between them.  I then end up 60 mm orso from the curvature corrector.    But i will try it anyway.  Curious whats coming out when not sticking to the rules.  

I bought it initially for my zenithstars.  Old models.  71 and 80 mm.   But the confusion started when searching for a coma corrector for a Quattro 8”.   Among the options i saw a baader mpcc.  And read that it means multipurpose comacorrector.  The first thing i thought was, “wait i have a mpcc”😬.   But my confusion and misreading caused also some confusion among you.  Sorry.  So bought an es mpcc for the right purpose and wondered if it could be used with a newton.  Im afraid not