First time seeing Saturn
Posted 09 March 2013 - 05:25 AM
I can't believe I sat outside looking at Saturn from 1:30ish til about 20 minutes ago. I just looked it with different eyepieces. Kept going back to the Baader eyepiece because it had the best views. My daughter says I need to get more of those. She said the others look fuzzy. And she is right, that Baader is like sharp and crisp. I think my next eyepiece is going to be a 10mm or maybe an 8mm..
Posted 09 March 2013 - 05:59 AM
Before you decide on which additional Baader to buy, (if this is the route you intend to take), perhaps try X2 Barlowing the 17mm to test the effect ?
I know the Barlow might not be the best and obviously introduces another lens into the optical train, but it should give you some idea regarding the view.
Personally, I think you'll only be able to use an 8mm on those especially clear nights and would therefore go instead, for a little less magnification. The 13mm perhaps ? I find this one "plenty good enough" for observing Jupiter, Saturn and Mars on most "average quality" nights.
Posted 09 March 2013 - 06:29 AM
Posted 09 March 2013 - 10:49 AM
Saturn is always a spectacular sight! I never get tired of it.
Any barlow will make the view dimmer. So will a higher power eyepiece. As you magnify the image, the light produced by the target spreads out over a larger image so there is less light per unit area and it appears dimmer.
You'll find that as you increase magnification, the image also becomes "softer" on most nights. This is due to atmospheric instabilities that blur the image. This condition is known as "seeing" and varies from night to night, and even from time to time during a particular night. When the seeing is poor, Jupiter can just look like a featureless ball. When it is excellent, you can see the Great Red Spot, and lots of detail in the bands. But it is the seeing which will limit how high you can go in magnification at any point in time.
I find that I can use my 13mm to get 150x on almost any night I observe. My 8mm produces 250x and I can only use that on about half the nights I observe. I find that I can only use my 5mm at 400x only on rare nights of perfect seeing, which only occurs a few nights a year around here.
So I agree with Tel, that a 13mm would be a good choice since it will get a lot of use. Personally, I prefer using eyepieces instead of a barlow whenever possible. With the long focal length of the SCT, you can easily find eyepieces that cover the range of magnifications that the scope can handle. With my shorter focal length scopes, the barlow is more of a necessity. But on the other hand, a barlow is an inexpensive way to extend your eyepiece collection compared to buying a bunch of eyepieces. I think the Astro-tech barlow and the GSO are decent brands, but there are many. Here's a couple of links for a 2x and a 2.5x:
Posted 09 March 2013 - 11:17 AM
Posted 09 March 2013 - 01:11 PM
Posted 09 March 2013 - 02:00 PM
Posted 09 March 2013 - 04:30 PM
Posted 10 March 2013 - 06:56 AM
I suggested the use of a X2 Barlow in conjunction with your 17mm Baader EP not only to give you an idea of the magnification you might expect at around 8.5mm, (the value produced from your 17mm combined with such a Barlow lens), but also to demonstrate the lesser contrast,(softer image), the use of Barlow lenses tend to yield when compared to the use of a single EP of equivalent focal length; (i.e. a 17mm + X2 Barlow = 8.5mm cf. an 8mm "straight" Baader EP).
The "straight" 8mm would doubtlessly give a sharper image with more contrast but again, I'd emphasise that such a relatively short focal length EP will only give its best on the clearest of nights with this size of 'scope.
Where however, the use of a X2 or X3 Barlow does come into its own, is when either is combined with a lunar/planetary imager, (such as a simple, adapted webcam). An essential tool in my view for such imaging.
You asked at one point which Barlow I use. In answer, I have two: a Celestron X2 Ultima SV Series and an Antares X3 but normally, as mentioned, I only use them for webcam imaging.
If however you still wish to buy one, (and they are excellent for lunar observing where plenty of light abounds), then perhaps also consider, a "Powermate" rather than a Barlow, with its lesser propensity to vignet ?
Hoping this helps,
Posted 10 March 2013 - 11:59 AM
Ok.. That all makes sense. I think I am going to get the 13mm as my next eyepiece then. Today, I am going to work on the antibacklash and see if I can get the tracking down smoother. I want to see if I can try to capture some pics..
If you want to do pics of planets (developed from videos with the frames combined to average out atmospheric effects), I definitely recommend a 2x Barlow. On my first try through the full process (2nd try overall using the camera...first try was just a warm-up), I was able to get quite a bit of detail for an 8" out of Jupiter on what cleardarksky.com called average seeing (see different thread in this forum), using a Barlow. Without a Barlow I can get some detail, but not nearly as much. Even though the Barlow may put you beyond the useful magnification, it does allow more pixels on target, which may enhance the *detected* details by the imager. There is still a limit--you won't beat the maximum useful magnification--but you may allow the detector's pixels to pick up something closer to the maximum useful magnification.
I have video without the Barlow that I haven't processed yet as intently, but a quick-and-dirty processing didn't show nearly as much detail. I will one day process them more rigorously, and post a comparison.
That said, I am a beginner at imaging, by no means an expert...but as a beginner, I was able to get more detail with the Barlow.
I second all of what Dan said -- for visual observing, you probably won't go past 8 mm unless you have a very good night. Also, for DSO imaging (which I have no experience with), a Barlow might hurt rather than helps, since it spreads the same amount of light over a larger area (ie, less per pixel, so noise is more likely to be a factor).
Posted 11 March 2013 - 04:42 AM
Posted 11 March 2013 - 07:03 AM