planetary imaging

[elkorunsfast]

Hey guys, i need your help once more. I was planning on getting the orion xx12g so i could do some visual observation but planetary imaging as well. If I were to connect a webcam such as the neximage, does anyone know if I can focus the camera or if I would need to get a barlow? I live in Woodstock Ny so light pollution is not very strong (on charts I think its a dark green zone). Would i need to get a 4x or 2x powermate/barlow? If anyone can help me that would be great.

thanks

[PeterCPC]

That will be a fantastic scope for visual use but not so good for AP. It can be done :

but I would suggest something like a SCT or Mak might be better for AP. I tried it with a flex tube Dob but rapidly concluded that an SCT would be easier.

Peter

[elkorunsfast]

I know it's not ideal but there some forums in which people say it's possible and there are people who do it. The thing is I can't afford both a dob and sct so I was thinking I could get a goto dob and do some planetary as well as visual. But if it's possible what would I need? Any good cameras for Mac and what Barlow? Thanks 

here is the forum

http://www.cloudynights.com/topic/485081-help-me-choose-camera-for-planetary-immaging-with-my-orion-xx12g-please-help/

[PeterCPC]

Yes, as I said, it can be done but it's not as easy as using an SCT. I can't answer the second bit as I don't do planetary imaging with a Dob. Perhaps someone else will come along and offer some advice.

Peter

[elkorunsfast]

Thanks for the help. Just one more question: what makes planetary imaging easier with a SCT than with a dob? Is there a particular reason why the SCT will be easier to image wth? Also will the SCT give finer images than the dob if at the same aperture? Thanks for the help

elko

[Stu]

So long as the dob tracks ok then I don't see why you shouldn't get good results with it. An SCT has a longer focal length natively so you would not need to Barlow as much, and because they are a more compact package they can more easily be put on an EQ mount to track well with nonfield rotation.

A goto dob, or standard dob on an EQ Platform would do just fine I think and may well suffer less from dew or cooling issues.

[neil phillips]

I think space cowboys results imaging planets show what can be achieved with dob tracking

[PeterCPC]

I can only speak about my own experiences. When I used a Dob it was very heavy to move about and it needed collimating before every imaging session but it was a flex tube.

My SCT is much easier to move about, its GOTO accuracy is excellent and it tracks very well. It also holds it's collimation. You pays your money etc.

Peter

[GuLinux]

I had a SC 200mm when I lived in Italy, and I used it for both visual observations and planetary imaging.

Having an equatorial mount was really comfortable for tracking, but the setup was too heavy, and half of the times I ended up not observing just because I didn't want to start assembling all that stuff.

Think about this aspect too, when choosing a telescope.

I can tell you what I did next: sold everything (well, actually my mount was stolen, but that's another story), bough a small Mak 127mm (5") for planetary imaging, and planning to buy a 12" dobsonian for visual observation.

The 5" Mak is cheap (you can get one for a little more than 300£) very handy, lightweight, has goto, and therefore tracking, and I can get it up and running in less than 5 minutes.

And its limiting resolving power is around 1 arcsecond, which is the best you can get for a night with an average seeing. Having a bigger aperture is in fact no help, if seeing isn't exactly perfect.

If you don't have the budget for both, like you said, I would just recommending choosing a different dobsonian, like this one on FLO, or maybe even without goto like this one. The Explore Scientific 12" is another cheap alternative, and it was my first choice until a few month ago (I then decided to wait for a sumerian optics for high portability, but that's another story).

Some people actually suggest starting without goto, because it helps a lot familiarizing with the sky, constellations, asterisms, and it will teach you a lot: I do agree with them, but ultimately it's your choice.

[elkorunsfast]

Oh I agree with you 100% I started off with a 6 inch dob and I still have it. I have experience in visual however not so much in photography. Do you recommend I try and start imaging with my dobsonian (without tracking) and familiarize myself with that?

[CraigT82]

It is definitely possible to do some planetary imaging with an untracked dob, but be prepared to pull some hair out!  Just getting the planet on the camera sensor is a challenge and some nights I've managed it, some times I couldn't (I don't have a dob but a skyliner tube on a skytee mount).  If you have a webcam of some sort and an illuminated reticle eyepiece you can quickly switch between them (gently!), use a parfocalising ring to make the reticle EP and webcam focus at the same point.  A webcam with a larger chip size is easier for this.  Once you have it on the sensor  and in focus you can let it drift across whilst collecting video before nudging the scope on to catch up just before it leaves the edge of the sensor, then repeat several times and you'll have a good chunk of video frames with a planet in it.   I use PIPP to then crop and centre the planet in each frame.

This is an image I got this Spring with the 8" skyliner tube on a skytee mount, using a DFK21 colour camera and baader 2.2x barlow.

Below that is a example of relative webcam chip sizes, bigger is better for this type of capturing!

.

[elkorunsfast]

Thanks everyone! I guess I'll have to think about what I want. I might try with a dobsonian since I was planning to get one in the first place. Last question, I saw someone mention that in unclear nights size won't matter. Does that mean that on an unclear night a smaller aperture would be more effective?

[dwayne dias]

Hey....have u heard about imsging newtonians...???..they are comparatively faster scopes with an f4 ratio...lighter in weigh, so its easier to handle and they even have shorter focal lengths so prime photography is easier as compared to dobs...i personally recommend that if you are interested in photograpgy then a dob is a little too much to handle...they are basically built for viewing but photography is possible too. I personally own an 8 inch dob...n it is huge n tough to andle. Also eq mounts that can take these payloads are pretty expensive. I suggest u do a little research on imaging ota's before investing in a dob.

[dwayne dias]

[dwayne dias]

https://stargazerslounge.com/uploads/monthly_2016_10/P_20161028_180302.jpg.ef2c63c65f0ed35676b118a6c6f306cc.jpg

I have built an eq mount of my own for my 8 inch...will try it out in a day or two...just to let u know...i face a lot of focus issues with my dob and i am unable to do prime Strophotography...so to gain focus i have even modified my dob focuser. 

 

The image i sent u earlier is a gso astrograph on a bresser eq mount and costs just the same as an 8 inch dob.

[CraigT82]

On 27/10/2016 at 13:36, elkorunsfast said:

Thanks everyone! I guess I'll have to think about what I want. I might try with a dobsonian since I was planning to get one in the first place. Last question, I saw someone mention that in unclear nights size won't matter. Does that mean that on an unclear night a smaller aperture would be more effective?

Not necessarily. The gist of planetary imaging is that you use fast frame rates to make the most of the fleeting moments of good seeing... The moments when the atmosphere is still and the image briefly snaps into sharpness. You get these moments even on nights of bad seeing so having the extra aperture is useful to make the most of those moments. However there are nights when the seeing is so bad its not even worth trying, small or large scope! 

There is a trade off though, between the size of the scope and its usability. A large scope will (theoretically) capture finer detail but it will be more of a pain to set up and use. Hence why many planetary images use SCTs in the 8-10" range, they've got enough aperture to get some good detail, have a good long focal length to get large image scale yet are still compact and light enough to drag out and set up night after night.

One of the best ways to get good planetary images, regardless of scope, is to make sure you're out there capturing data every chance you get, night after night.  You never know when you'll get one of those perfect nights!