The Astro-Imaging Thread

[Epox75]

What i did is looking for doublet on astrobin and started browsing the pictures i liked the most. I've seen very nice images taken with WILLIAM OPTICS Megrez 90mm Doublet Apochromatic, with Long Perng 100mm f/6 doublet and with the SkyWatcher 80ED APO Doublet FPL-53  (https://www.astrobin.com/gear/24678/skywatcher-80ed-apo-doublet-fpl-53/) and considering the price comparison and the money I've already spent so far on my equipment I would go for the cheaper solution. I'm not sure thou about mounting the doublet over my c11, I know it looks cool and whatsoever but still my mount has cogs and cogs deteriorate overtime, especially if lifting heavy weights. My mount is CGEM DX and it's a mount that can take also a C14 but I am actually terrified thinking about leaving it even if just for repair. I think the less weight i'll put on it, the longer it will survive

And talking about used I've just seen this guy here in the netherlands selling this: http://www.te-les-koop.nl/index.html?BekijkAdvertentie.php&key=23942

Basically it say: almost new, rarely used, with microfocuser and an eq mount not motorized but who cares.. do you think I should go for it?  (Edit:  I don't think is the ED series so no matter) 

Edited May 7, 2017 by Epox75

[_Augustus_]

31 minutes ago, Epox75 said:

What i did is looking for doublet on astrobin and started browsing the pictures i liked the most. I've seen very nice images taken with WILLIAM OPTICS Megrez 90mm Doublet Apochromatic, with Long Perng 100mm f/6 doublet and with the SkyWatcher 80ED APO Doublet FPL-53  (https://www.astrobin.com/gear/24678/skywatcher-80ed-apo-doublet-fpl-53/) and considering the price comparison and the money I've already spent so far on my equipment I would go for the cheaper solution.

I would be looking for images taken with similar cameras to yours as well, as that can affect image quality.

[Green Baron]

Errr .... APM sell that set new for 600,- 665,-. The refractor is an achromat. Has it even a glass lens :-) ?

Edit: i gave false information about the refractors vom LZOS. The sizes from 123mm on are still on sale. Example.

So easy to spread fake news because of information from another forum. Sorry ....

Edited May 7, 2017 by Green Baron

[Epox75]

1 hour ago, Green Baron said:

Errr .... APM sell that set new for 600,- 665,-. The refractor is an achromat. Has it even a glass lens :-) ?

Edit: i gave false information about the refractors vom LZOS. The sizes from 123mm on are still on sale. Example.

So easy to spread fake news because of information from another forum. Sorry ....

No problem seen the prices anyway is something out of my league even second hand http://www.te-les-koop.nl/index.html?BekijkAdvertentie.php&key=24428

But actually this second hand dutch market is not bad at all, this one looks very interesting for instance: http://www.te-les-koop.nl/index.html?BekijkAdvertentie.php&key=24498. 600 euros, triplet with fpl53 glass, very good conditions... yummy. 

[Green Baron]

Wow ! There is a 152/1200 on sale with a strehl of .99 ? I would give my 115/805 away, but my poor G11 would surely straddle. No way ...

TS (http://www.teleskop-express.de/shop/index.php/language/en/) have a good reputation. I actually have the exact same small flattener/reducer 279. The Orion's sword i showed off was made with it and you can see no vignetting with the 4/3-sensor. If the small refractor has no faults and a reasonable focuser for photography then why not.

I found this one on their site but attention, it has the super expensive feather touch focuser and is probably not directly comparable to the tube from the offer ! Good luck

[Epox75]

An apo it is something I will buy for sure but anyway there's no point in buying it until i get some confidence with the camera and processing.The C11 can take a lot of light compared to apos and I live under a light polluted sky because of an industrial site, completely illuminated with mercury-vapor lamps, not far from my home. Fortunately within a year they will replace the lightning system with shielded LED lamps and it will be also an automated system that will keep the lights off if they are not necessary. This will improve drastically the quality of the sky here since I don't live in a big city.  That will be probably the moment I will buy an apo, for now I'll save some money waiting for the day

And when I will have the apo I will do something like this:

 

Edited May 8, 2017 by Epox75

[Green Baron]

This is one possibility when you have a huge mount compared to the weight you put on it. It looks like the guy uses less than half of the mounts capacity. I have the same refractor, but i can only use it as a guide scope because of the crappy focuser.

Balance is the issue with this style of setup because it might be difficult to have a comparable weight on both rails.

The vixen style foot of the ES ED80 is indeed a problem if you don't have a vixen style mount (proprietary stuff :-)). But you can screw it off and use two rings instead like i did, which gives even more flexibility. I can use the small refractor alone with a common 2" rail or mount it with two screws on top of the apo as a guide scope. I even dare to claim that that is the cheaper variant ...

Saving the money for a real thing is always a good idea !

 

Edited May 8, 2017 by Green Baron

[Epox75]

18 minutes ago, Green Baron said:

I have the same refractor, but i can only use it as a guide scope because of the crappy focuser.

 

Why crappy, It doesn't hold the focus? I also have a crappy standard focuser on my C11 but I have managed to use the histogram as reference when focusing and that saved a lot of paranoia (focused objects are brighter so when the histogram reaches its peaks it mean that the best focus has been reached). A bahtinov mask for my c11 is incoming and that should make things even easier. I've also head about people wedging or gluing larger plastic wheels (like toy car wheels, pudding stamps) on their focuser in order to achieve more precision.  

[Green Baron]

31 minutes ago, Epox75 said:

Why crappy, It doesn't hold the focus? I also have a crappy standard focuser on my C11 but I have managed to use the histogram as reference when focusing and that saved a lot of paranoia (focused objects are brighter so when the histogram reaches its peaks it mean that the best focus has been reached). A bahtinov mask for my c11 is incoming and that should make things even easier. I've also head about people wedging or gluing larger plastic wheels (like toy car wheels, pudding stamps) on their focuser in order to achieve more precision.  

It slides out when there is anything heavier than a small eyepiece, even when all screws are fastened. For example, i have 100° eyepieces but they are too heavy. So is the dslr camera. My other complaint is that it only has one screw to tighten the fitting. There is always a few degrees of play in the system. And it doesn't close very will, mirror and small eyepiece turn slowly but steadily towards the center of the earth.

A reasonable focuser has 3 screws 120° apart like a star, so that nothing can wobble.

[Epox75]

25 minutes ago, Green Baron said:

It slides out when there is anything heavier than a small eyepiece, even when all screws are fastened. For example, i have 100° eyepieces but they are too heavy. So is the dslr camera. My other complaint is that it only has one screw to tighten the fitting. There is always a few degrees of play in the system. And it doesn't close very will, mirror and small eyepiece turn slowly but steadily towards the center of the earth.

A reasonable focuser has 3 screws 120° apart like a star, so that nothing can wobble.

That's bad, mine has two and i have to use calipers to turn it just a bit tighter of what i'm able to reach with my bare hands. Have you tried to put something inside the focuser to simulate the pressure that other screws may do on the other side? I would probably try something like a little piece of tape with gripping/anti-slide material. 

[Green Baron]

Yes, i tried with paper (is has enough space :-))). Also i used a file to roughen the surface of the part that fits into (not the eyepieces of course).

But since a am used to the 2,5 inch feather touch (FT) on the apo i don't tinker with that thing any more. The FT has three screws and they fix things without the slightest force, just thumb and index and a stretched away little finger. It is rather a problem to get things out when angled than to fix things.

Edited May 8, 2017 by Green Baron

[Epox75]

Two more Moon pictures from the 5th of May. These are taken with a 0.63x focal reducer (1760mm focal lenght)

[_Augustus_]

My Meade 2080 is finished. I may try imaging Jupiter with it tonight.

[Epox75]

The last stuff arrived! And amazingly I'll have to chance to test the autoguiding right away.. no clouds tonight!

[kurja]

New hardware - and no clouds? You must be trippin'

[_Augustus_]

58 minutes ago, kurja said:

New hardware - and no clouds? You must be trippin'

It's our lucky break, I suppose.

[Epox75]

3 hours ago, kurja said:

New hardware - and no clouds? You must be trippin'

No Worries, some clouds will be incoming later tonight .. just to spoil my fun. 

Anyway incredibly I didn't encounter big problems and the mount is already guiding like a charm, without anti-backlash or PEC. I'm a bit upset for the fisheye effect my reducer is causing at the edge (but not so edge) of the image.... I guess I'm going to bother my vendor for a replacement with a better one

 

[Epox75]

2 hours and a half into autoguiding.. how does it look btw? 

[_Augustus_]

First light with the 2080 went well, but I forgot to take a flat frame....

http://www.astrobin.com/295249/?nc=user

[Green Baron]

8 hours ago, Epox75 said:

No Worries, some clouds will be incoming later tonight .. just to spoil my fun. 

Anyway incredibly I didn't encounter big problems and the mount is already guiding like a charm, without anti-backlash or PEC. I'm a bit upset for the fisheye effect my reducer is causing at the edge (but not so edge) of the image.... I guess I'm going to bother my vendor for a replacement with a better one

 

Distance chip/reducer is submillimeter work and sometimes (normally ?) manufacturers data needs ... interpretation :-)

Start with the distance from the manual/tech sheet of the reducer, if you have distortion put in variations like 1mm shorter or longer and see whether it gets better. An element that allows adjustment is a nice idea. I can take a photo if you like ?

Still cloudy here, showers out over the sea .... :-/

[Epox75]

7 hours ago, Green Baron said:

Distance chip/reducer is submillimeter work and sometimes (normally ?) manufacturers data needs ... interpretation :-)

Start with the distance from the manual/tech sheet of the reducer, if you have distortion put in variations like 1mm shorter or longer and see whether it gets better. An element that allows adjustment is a nice idea. I can take a photo if you like ?

Still cloudy here, showers out over the sea .... :-/

Thanks for the tip! Unfortunately in the corrector's box there was nothing but the corrector (this one btw: http://www.robtics.nl/product_info.php?cPath=30_184_255&products_id=132&pID=132&language=en ). The filter wheel was all the way in inside the visual back, next time i'll try with a couple mm distance and see if it get worse or better

[Green Baron]

I searched "Robtics f6.3 reducer backfocus" but could not find info. But the original Celestron one showed up in the searchlist, it has 115mm, measured from chip-plane to wherever, usually the end of the thread on the reducer casing facing camerawards. So, better call robtics.

Add 1mm for the pass through the filter glass, deduct the camera backfocuss and the filterwheel. Cam backfocus is the distance from camera chip to end of camera casing, some cameras have a mark at the side. Example: my reducer/flattener has 80mm backfocus when used with a focal length of 800mm. Minus 17mm camera backfocus, minus 16mm filter drawer, +1mm filter thickness makes for *scratchhead* 48 mm of rings and tubes and things to get the chip to the correct distance from the reducer. Usually not all reducers are the same and some cameras were made on monday morning, so it may be a good idea to have an element in between that you can screw in and out to vary a little bit. With the right distance the image should be ok. And ask robtics what the diameter of the corrected field without noticeable vignetting is. Answer to such questions always show me whether the person on the other end of the line know their job ;-)

Tip: use distance things with a usual diameter, like M42 (2") so that the tubes will not be the cause for any vignetting and you can use them anytime you need some distance between any 2" focuser and whatever.

:-)

Edit: all items in the queue must have threads so that they can be screwed together without tilt. We don't want a tilted camera chip. The element used for adjusting must have a counter-ring to avoid tilt of an otherwise loose thread.

Edited May 11, 2017 by Green Baron

[Epox75]

The 1st raw untouched, just stretched histogram. I also had to take a screenshot because I cannot manage to save the image like this

[Green Baron]

Nice ! f/6.3 or f/10 ? What was the exposure time ?

 

[Epox75]

1 minute ago, Green Baron said:

Nice ! f/6.3 or f/10 ? What was the exposure time ?

 

Sorry was editing my post with the infos: it's f/6.3, Lumicon Deepsky Filter, 30x2min exposure at unity gain (139 gain 21 offset - it's one of the 3 default exposures of the camera). 20 flats, 20 darks, 50 bias integrated.