Planetary imaging is a little (OK, quite a little!) different from DSO imaging. Here's an "off-the-cuff" list of issues to keep in mind to get the best possible image:

1. Seeing is King. You can't get great planet images every night of the year. This type of imaging is highly seeing-dependent, so you just have to take what mother nature gives you. Often as not, that will be a night off
   
2. Work at the maximum effective focal length the seeing will give you. Most good planet images are done around F20 to F30. This means using a barlow or powermate. On very rare occasions, one can go as high as F50, but don't plan on it. I can count the number of nights per year that support F30 imaging in my Minnesota location on one hand...and have fingers left over.
   
3. Focus is critical. It is exceedingly difficult to achieve "perfect" focus when working at high magnifications...the image will usually be impaired by turbulence, moving in and out of focus, deforming, etc. even when you don't touch a thing. I recommend using a focus mask on a nearby bright star to achieve critical focus, then move the scope to the planet (resist the urge to touch anything!). I prefer the diffraction spike method, but whatever works for you is fine:
   http://astronomy.qteaser.com/diffspike.html
   (Note - if temps are dropping, SCT users will need to refocus often - like every 5 or 10 minutes)
   
4. Collimation is Queen. Even if you do everything else right and the seeing is perfect, if your collimation is off, your images will still be soft. Collimate your scope with any barlows, diagonals, etc. that you will be using to image in place:
   http://legault.club.fr/collim.html
   
5. Beware of rotation. Especially with Jupiter, we have to limit the total "time on target" for any given image (or stack of images) to prevent rotation of the planet from blurring the details. For Jupiter, the recommended maximum duration from first exposure in the series to the last exposure is 3 minutes. I usually find this is enough time to capture a decent stack for Saturn & Mars, but have occasionally bent the rules and gone as long as 5 minutes without noticing a problem.
   
6. Avoid imaging at low elevations. Turbulence is much worse at lower target elevations...try to do your imaging as near to zenith or transit of the meridian as possible. I consider 50 degrees elevation the absolute minimum for really good quality images.
   
7. Be patient. Seeing will "come and go" over the course of the evening. Set up the scope & camera, and watch the monitor. You will soon get a feel for the conditions, and a sense of when seeing is improving or worsening. Try to time your captures to coincide with periods of generally better seeing.
   
8. It's usually steadiest before dawn. I would say virtually all my better planetary images have been made after midnight, up to an hour or two before dawn. This is when the local atmosphere is most settled.
   
9. Don't be afraid of the Moon! One of the great things about planetary imaging is that you do not need a "dark sky" site and a moonless night to get great images. I have taken "keepers" with a 90% full moon less than 15 degrees away from my target, and in conditions with poor transparency and high light pollution where DSO imaging would have been impossible.

Have fun!

Chuck

 

---

Chuck Reese
CDIP Certified: Nebula, Galaxy, Solar System, Stars & Clusters Imager
CDIP Mentor: Nebulae & Solar System Categories
For information on the Certified DSI Imager Program, see:
http://autostarsuite.net/forums/1427/ShowForum.aspx

Chuck -

I am new to imaging. I currently have my DSI III configured - LX200]focuser]focal reducer]DSI.

Can I add a diagonal or flip up mirror before the DSI, and where in the sequence would it go?

Similarly, adding a Barlow?

Frank