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M Astronomy

Imaging with a Star Adventurer

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I use a bahtinov mask and take 5s exposures at isi 800 or 1600 depending on the brightness of the star I’m using for focus. It’s much easier to see the relative position of the diffraction spikes than trying to use live view, and can usually get it nailed down inside a minute if you start from somewhere close to infinity focus

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Hi

Im a total novice. I’ve just received my unit but the weather is no good at the minute. One thing I don’t understand when I read through the posts is the guided, unguided bit. 

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Posted (edited)
8 minutes ago, Cyprio42 said:

One thing I don’t understand when I read through the posts is the guided, unguided bit. 

Unguided is just with a camera looking through a scope or lens. 

Guided is with an additional camera taking short pics through a Guidescope to correct the error in order to get better (and longer) exposures through your imaging setup. 

In both cases the motor is turned on, but in the latter an additional cable (ST4) is plugged aside the mini USB socket. 

Edited by FaDG

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+1 on FaDG and I just want to make it more simple, thats being done with camera looking thru small scope called guidescope and a software like PhD2, it centers a star and registers the movement of it. If the star is out of the center the software will tell to you mount to go faster, slower, left right etc.. :)

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1 hour ago, FaDG said:

Unguided is just with a camera looking through a scope or lens. 

Guided is with an additional camera taking short pics through a Guidescope to correct the error in order to get better (and longer) exposures through your imaging setup. 

In both cases the motor is turned on, but in the latter an additional cable (ST4) is plugged aside the mini USB socket. 

Thanks for your advice?

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50 minutes ago, serbiadarksky said:

+1 on FaDG and I just want to make it more simple, thats being done with camera looking thru small scope called guidescope and a software like PhD2, it centers a star and registers the movement of it. If the star is out of the center the software will tell to you mount to go faster, slower, left right etc.. :)

Thanks for your advice?

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SWSA, Canon 1100D, MTO-11CA + homemade 0.7x focal reducer

 

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Howdy, is this thread still active?

I'm curious if anyone can recommend a longer focal length for my nikon aps-c sensor dslr to image DSOs. At the moment my longest lens is 85mm. I'm considerting picking up a "bargain" manual focus 300mm f4.5 for a couple hundred bucks. Would this be a good choice, or a bit too long?

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Posted (edited)
15 minutes ago, bokchoy ninja said:

Howdy, is this thread still active?

I'm curious if anyone can recommend a longer focal length for my nikon aps-c sensor dslr to image DSOs. At the moment my longest lens is 85mm. I'm considerting picking up a "bargain" manual focus 300mm f4.5 for a couple hundred bucks. Would this be a good choice, or a bit too long?

I think most people would say it's a bit long, and you can probably get an 'old glass' 200mm f/4 lens for less, but if you have a well adjusted polar scope and are good at getting alignment with your SA, there's no reason why not to try it. 

 

Edited by Gfamily

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Posted (edited)
7 minutes ago, Gfamily said:

I think most people would say it's a bit long, and you can probably get an 'old glass' 200mm f/4 lens for less, but if you have a well adjusted polar scope and are good at getting alignment, there's no reason why not to try it. 

  

I suppose you're right, but I just don't want to waste money on a lens that I can't manage (despite being inexpensive). Any issue with a bargain lens that doesn't have ED glass? I'm thinking of, for example:

https://www.keh.com/shop/nikon-200mm-f-4-ai-manual-focus-lens-52.html

Thanks!

Edited by bokchoy ninja
wrong link

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Posted (edited)
10 minutes ago, bokchoy ninja said:

I suppose you're right, but I just don't want to waste money on a lens that I can't manage (despite being inexpensive). Any issue with a bargain lens that doesn't have ED glass? I'm thinking of, for example:

https://www.keh.com/shop/nikon-200mm-f-4-micro-if-ai-manual-focus-lens-52.html

Thanks!

I'm mostly a Pentax user, so am not really able to talk about other brands; however, I'd say I'd start by checking all the reviews you can find and check out how much CA the lens demonstrates to users. 

As you've identified, there's no need for a lot of the features of modern lenses; so no need for AF* or IS - all you need is a manual aperture ring and good glass. Does that one have manual Aperture? 

* though it seems that AF can be useful for some brands where you can use laptops to measure and adjust the quality of focus via USB cable.

Edited by Gfamily

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11 hours ago, Gfamily said:

I'm mostly a Pentax user, so am not really able to talk about other brands; however, I'd say I'd start by checking all the reviews you can find and check out how much CA the lens demonstrates to users. 

As you've identified, there's no need for a lot of the features of modern lenses; so no need for AF* or IS - all you need is a manual aperture ring and good glass. Does that one have manual Aperture? 

* though it seems that AF can be useful for some brands where you can use laptops to measure and adjust the quality of focus via USB cable.

Thanks for the reply!

I'm considering a 180mm lens which is 5 inches long and weights 1.8 pounds. What I'm concerned about is: there's no tripod collar on it, and no obvious place to mount one. Do you think, with this weight and size, that a Nikon F-mount would be able to safely support it? It's so difficult to find capacity ratings for this.

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3 hours ago, bokchoy ninja said:

Thanks for the reply!

I'm considering a 180mm lens which is 5 inches long and weights 1.8 pounds. What I'm concerned about is: there's no tripod collar on it, and no obvious place to mount one. Do you think, with this weight and size, that a Nikon F-mount would be able to safely support it? It's so difficult to find capacity ratings for this.

Can you possibly buy/make/modify a tube ring or support for the lens. So that the lens is mounted to the SA and the camera then mounted to the lens??

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17 hours ago, bokchoy ninja said:

Howdy, is this thread still active?

I'm curious if anyone can recommend a longer focal length for my nikon aps-c sensor dslr to image DSOs. At the moment my longest lens is 85mm. I'm considerting picking up a "bargain" manual focus 300mm f4.5 for a couple hundred bucks. Would this be a good choice, or a bit too long?

Hi, and thanks for posting. My experience with longer FL lenses (Canon) with the SA mount is that at 300mm FL expect up to 3 minutes sub-exposures if you get polar alignment and payload balance right. That was with a fairly light 75-300 mm zoom lens and which together with a Canon 600D weighed in at 1,164g (2.57lbs). The lens was simply connected to the camera with no additional support. Mostly however I use shorter, faster FL optics on my SA to provide long enough exposures for my imaging conditions in a Mag 5.0 sky.

Good luck coming up with your decision and don't forget to post your successes on SGL.

Best Regards,
Steve. 

 

 

 

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So than I will need a lens collar for my 135mm samyang? Or it will be fine attached to the camera? It weights somewhere around 800g

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10 minutes ago, serbiadarksky said:

So than I will need a lens collar for my 135mm samyang? Or it will be fine attached to the camera? It weights somewhere around 800g

I haven't used one on my 135mm. Just attached to camera

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You can`t buy lens collars for the 135 sadly. I used a canon 200 mm f2.8 usm on my SA and its around the same weight. It should be ok on the bracket with good PA and balance...

Alan

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I made my own lens support for a 200mm M42 fit lens. 

IMG_20190331_154857.thumb.jpg.48ddbae78472429073f277af5748a7c3.jpg

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Hmm... I really don't want to have to jerry-rig a 2lb lens onto a makeshift lens mount. Can anyone recommend a lightweight, large-ish aperture lens that would be suitable for DSO imaging and would be light enough to hang unsupported on the camera?

I suppose I could go with a 70-200mm with a tripod mount already attached, but those run at around 4 lb, and I imagine I'd be getting very close to the weight limit of the Star Adventurer at that point. (2lb camera + 4lb lens + 3lb counterweight) --> doesn't seem to leave room for an autoguider.

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Posted (edited)

I have used the 200mm lens above on my canon Eos 450 on my SA with no extra support. Just the camera mounted to the SA. 

The above set up was to see if I could make use of my GPCam with the lens on the SA. It's certainly not "Jerry rigged". Lol. It's precision designed in CAD and printed out on my own printer ;-). I wouldn't risk my own stuff if it wasn't robust enough. Plus I am a design engineer. :-)) 

?

Edited by Bobby1970
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11 minutes ago, Bobby1970 said:

I have used the 200mm lens above on my canon Eos 450 on my SA with no extra support. Just the camera mounted to the SA. 

The above set up was to see if I could make use of my GPCam with the lens on the SA. It's certainly not "Jerry rigged". Lol. It's precision designed in CAD and printed out on my own printer ;-). I wouldn't risk my own stuff if it wasn't robust enough. Plus I am a design engineer. :-)) 

?

Hey that's fair enough, I wasn't trying to criticize your design :)  

In my case, lacking access to a 3D printer, my solution would certainly involve some jerry-rigging. Interesting that you've been able to use your 200mm lens without support. How heavy/long is it, out of curiosity?

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41 minutes ago, bokchoy ninja said:

Hmm... I really don't want to have to jerry-rig a 2lb lens onto a makeshift lens mount. Can anyone recommend a lightweight, large-ish aperture lens that would be suitable for DSO imaging and would be light enough to hang unsupported on the camera?

I suppose I could go with a 70-200mm with a tripod mount already attached, but those run at around 4 lb, and I imagine I'd be getting very close to the weight limit of the Star Adventurer at that point. (2lb camera + 4lb lens + 3lb counterweight) --> doesn't seem to leave room for an autoguider.

Hi there!

As a uk site, not many of us (still) work in pounds.

2.72kg would not really trouble the SA, as it can comfortably cope with that. The literature states up to 5kg. You don’t count the weight of the CW in this. So there is room to add a lightweight auto guider too.

 

 

 

 

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14 minutes ago, bokchoy ninja said:

Hey that's fair enough, I wasn't trying to criticize your design :)  

In my case, lacking access to a 3D printer, my solution would certainly involve some jerry-rigging. Interesting that you've been able to use your 200mm lens without support. How heavy/long is it, out of curiosity?

I know you were not really criticising. Lol. My comment was all a bit tongue in cheek. ;-). 

 

My lens weighs in at around 700g. 

It's around 190mm long with the dew shield/hood extended. 

 

 

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Thanks for the replies and for the advice!

The Nikkor 180mm f2.8 ED AIS weights 800 grams. The salesman at KEH says if the lens doesn't have an included mounting point, then the camera can handle its weight. I ordered it and will report back as to how angry my camera feels at the offense.

Also interesting that you say the 5kg capacity of the SA doesn't include the counterweight. But either way, my longest lens will likely be the 180mm so there will be margin for an autoguider. Going out this upcoming weekend to get some widefield shots with a 14mm and break in the SA. Wish me luck!

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3 minutes ago, bokchoy ninja said:

Thanks for the replies and for the advice!

The Nikkor 180mm f2.8 ED AIS weights 800 grams. The salesman at KEH says if the lens doesn't have an included mounting point, then the camera can handle its weight. I ordered it and will report back as to how angry my camera feels at the offense.

Also interesting that you say the 5kg capacity of the SA doesn't include the counterweight. But either way, my longest lens will likely be the 180mm so there will be margin for an autoguider. Going out this upcoming weekend to get some widefield shots with a 14mm and break in the SA. Wish me luck!

I’ve just started imaging on a SA with a Nikkor 180mm. The total weight of my camera and lens and dovetail and remote trigger is 4 1/4 pounds ? (1.92kg)

The lens seems to present no trouble without a bracket holder. I took this last week - 16 x 120s ISO400 F2.8

 

 

5F1EC8FD-B7F9-4452-9356-F2BBE83B18C8.jpeg

8576C029-AF0F-4AD8-A403-C1E9C2B23A57.jpeg

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