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Mizar and Alcor


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These are perhaps my most favourite collection of stars in the sky, probably because it was one of the first objects I looked at when I got my first scope! Always beautiful to see and easy to split. And finally I managed to get a half decent picture of the group with my afocal setup!

My setup was: 90mm Evostar, EQ3-2, 25mm SW lens and TAL x2 Barlow, Scopeteknix ST98 and Sony DSC-W130 Digital Camera.

The first picture was without the barlow and the second with. Didn't think they came out too bad with my afocal setup. Now if someone was willing to donate me a DSLR I'd greatly appreciate it. :)

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What magnification did you use to split Mizar?

If it's clear tonight, I'm going to try and go on a bit of a double star marathon. I've never seen a double star before, so don't know what to expect to be honest.

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Mizar is probably one of the easiest to split. I split with my largest eyepiece (25mm). On my 90mm Evostar it gave me 36x mag for the first pic and then used the 2x barlow giving me 72x mag to get the closer shot.

I quite like double star viewing... well when my moods up for it! But I like them because you can get different coloured doubles and thats always a nice view. Better then faint gray smudges or something! haha

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Hey JimStan, nice job on doing that to my pic. So surprised at what that little compact digital took! There's hope for afocal photography yet! haha

@nightfisher: Actually didn't use any settings other then the fully auto setting on the camera. Well I think it was full auto, may have used the landscape setting on the dial! Can't remember now!!

But anyway its just a small compact digital and this was an afocal picture. Had a digital camera adaptor to attach it to the scope to keep in steady and then all i did was put it on the timer so that the scope has a chance to stop shacking before the picture was taken.

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hi. just fyi - if you were really interested in finding out what settings you used, and you still have the original jpg from your camera, that kind of info is often stored by the camera in the exif data of the file.

Exchangeable image file format - Wikipedia, the free encyclopedia

many image viewing/editing programs will have the option in a menu somewhere to "show exif data" or "show meta data" or something like that. =)

(i checked the files you attached, but they don't appear to show the camera settings. this could be that your camera just doesn't save that info, or it could be because the images have been edited and re-saved and the program has written its own exif data).

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Great to see what can be done with a very simple and straightforward setup!!

I was chatting to a friend last night who is a keen birder - he had tried a digiscoping mount on his finderscope but found the process a bit fiddly - very kindly he is posting the mount to me in the next day or two - so I can't wait to have a go.

The model is:-

Kay Optical - Telescopes and Binoculars Sales, Servicing and Repairs

As yet I haven't got a motor drive but it is very interesting to see what can be achieved without one and particularly with a S/W Mak 127!!- so I shall be looking out for afocal images with interest and any details of exposure settings!!!

If anyone has any experience of this mount any advice would be appreciated.

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@pellgarlic: Well I checked out the file after you mentioned it. Didn't really think to do so before. What I found from the original image that fellow re-done for me is:

f/5.8, 1/8 sec exposure, ISO800, Esposure Bias 0 Step. 21mm Focal Length, max aperture 3 and Metering Mode Pattern.

That seems to be all the relevant information for that image thats on the file as far as I know. :-)

@Nibor: That's very similar to the mount I used to take these images. To me it's a very stable digital camera mount and quite easy to use once you've practiced with it a little.

However the downsides are that it's quite heavy so the scope will need balancing to get it moving smoothly, and also it can be a bit of a pain on oddly shaped eyepieces or short one's. You'll see when you get it. :-)

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@pellgarlic: Well I checked out the file after you mentioned it. Didn't really think to do so before. What I found from the original image that fellow re-done for me is:

f/5.8, 1/8 sec exposure, ISO800, Esposure Bias 0 Step. 21mm Focal Length, max aperture 3 and Metering Mode Pattern.

That seems to be all the relevant information for that image thats on the file as far as I know. :-)

seems about what i'd expect for a compact camera, although sometimes it will list the "program/mode" that was used as well... this info can be handy if you want to reproduce a shot, and your camera has a "manual" mode (where you can dial in the specific shutter speed, aperture and iso you want) or tweak it by altering one of the values.

yeah, a dslr would produce a slightly better image, in that it wouldn't have to use as high an iso as a compact due to the larger sensor. on a related note, i've recently been toying with the idea of a acquiring a cheap 500mm mirror lens for my dslr... =P

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@pellgarlic - It didn't list what mode it was, but it is a fairly old camera by modern standards. Also it was on full auto when I took these shots as well. Also took a look at the programmable mode but it's even more limited. Can't even set the ISO above 400 on it.

I do have a DSLR but it's the first time I've ever had one and I'm still learning how to use it. Needless to say so far it's been mixed results, but I'm learning slowly though.

@Nibor - I took the liberty of creating an album on photobucket of all my afocal photography (well the good ones anyway!). It's not spectacular stuff but it shows that afocal isn't all pointless. You can get good results, just nothing special. But at least you're not limited to Luna shots. :-)

Afocal Amateur Astronomy pictures by benjy85pb - Photobucket

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I do have a DSLR but it's the first time I've ever had one and I'm still learning how to use it. Needless to say so far it's been mixed results, but I'm learning slowly though.

same as with anything, the more control the device allows the user, the longer it takes to fully get to grips with it. in the end, i think fully manual control is well worth it for certain things - holiday snapshots are "good enough" when using the auto modes, but something like astrophotography definitely benefits from the manual control (not that i've done much of it myself tbh... =P ).

at the risk of telling you how to "suck eggs", and in the event that it might help anyone else, it basically comes down to understanding the balance between three factors - shutter speed, aperture, and "ISO" (i put that in quotes 'cos although it's used in digital cameras, and in practice has pretty much the same effect as it did with film, it's more a useful "re-purposing" of the term for the digital world than an exact duplicate of function). adjust any one of those, and you change the exposure.

so, first, it's best to put the camera in "manual focus" mode, and set it to near infinity. then, put your camera in "M" (manual) mode, find the controls for setting each of these three values, then take a photo. if the photo comes out too dark, you need to increase the exposure, by either (a) lengthening the shutter speed (e.g. from 1 second to 10 seconds), (:) enlarging the aperture (e.g. from F8 to F2.8 - conversely, the smaller the number, the larger the aperture), or © increasing the ISO (e.g. from ISO 200 to ISO 800). if the photo is too light go the other way. =)

set the ISO too high, and your picture will look grainy. set the shutter speed too high, and you'll get "motion trails" on the stars. set the aperture too wide can mean it's difficult to set the focus on what you want (less of a problem with astrophotography i believe, as the stars are all pretty much at "infinity" =P ).

so it's just a case of finding the best balance between shutter speed, aperture and ISO. that best balance will lie in different places for different purposes. doing astrophotography, using a tripod, shutter speed can safely be quite long (although as i say - if you go too long, you'll get "star trails" - sometimes this effect is desirable though =) ). aperture should be as wide as possible to allow in as much light as possible. and i'd stick to the lowest ISO you can get away with - that's the one factor that generally has an undesirable effect when increased - the other two can work well in either direction, depending on your desired outcome.

HTH =)

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@pellgarlic - It didn't list what mode it was, but it is a fairly old camera by modern standards. Also it was on full auto when I took these shots as well. Also took a look at the programmable mode but it's even more limited. Can't even set the ISO above 400 on it.

I do have a DSLR but it's the first time I've ever had one and I'm still learning how to use it. Needless to say so far it's been mixed results, but I'm learning slowly though.

@Nibor - I took the liberty of creating an album on photobucket of all my afocal photography (well the good ones anyway!). It's not spectacular stuff but it shows that afocal isn't all pointless. You can get good results, just nothing special. But at least you're not limited to Luna shots. :-)

Afocal Amateur Astronomy pictures by benjy85pb - Photobucket

benjy85pb

Many thanks for your comments and the link to your pix. I will be very pleased if I can get results like yours!! - I forsee some experimention with exposure settings forthcoming when the skies clear!!

Robin

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@Nibor - No problem mate. And don't worry, pictures like that are surprisingly easy to achieve one's you've done a bit of fiddling around. Just takes a bit of patience and trail and error. :-)

@pellgarlic - Indeed you were so I chose to ignore it for being somewhat condescending. Although I'm new to DSLR's and their use in this field I do have the basic awareness of how to use them. But putting that into practice and gaining experience in using them effectively is different then just reading about it or being told. So yes I am inexperienced at them but I'm slowly gaining experience in how to use them to best of my abilities and capabilities.

As you can see from my photobucket, they're not amazing pictures like you see here but I've learnt a lot from just the afocal work and have made steady improvements, and will continue to do so. :-)

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