Posts Made By: Michael Connelley

Hello:
I have one and it's a fun, cute little scope. Optically, it's very good, and I think it'd be hard to show that any other ~4" APO is significantly better in terms of optical quality. The wide field views can't be beat. With the 31mm Nagler, I can get a 5 degree field of view which make things like the California Nebula or the North America AND Pelican Nebula, or the whole Veil Nebula possible, if not easy. Since the focal length is so short, a good barlow is necessary for any kind of planetary observing, and a 5x powermate would go well with this scope.
A fun story of mine is that once we had our Sky90 set up next to a C11 at a dark site (12,000ft. on Mauna Kea). With both scopes pointed at the Virgo cluster and using similar eyepieces, we could see the same number of galaxies in both scopes! The C11 could see fainter, but the Sky90 had a wider field of view, so in the end it came out the same. Other scopes probably give you more bang for the buck, but the Sky90 is a real peasure to use.

Cheers
Mike Connelley

Hello:
Try the following experiment. Make a cardboard disk about 3.1" in diameter, with a hole so you can stick it on the backside of your spider. The next time the seeing is good, put this on the back of your spider to increase your central obstruction by 5%. See if you can honestly see a difference. If you can, then I'd say moving to the smaller diagonal is worth it. If no, keep what you have and save the money. I recently chose to increase the secondary of my 12.5" f/6 from 2.1" to 2.6" to get added field of view (the central obstruction is small in either case).

Cheers
Mike Connelley

Hello:
Ihad a similar problem with my telrad. I solved it by putting a few bits of duct tape (is there any problem it can't solve?) on those little plastic tabs to thicken them up a bit, and now my telrad locks in fine. The metal screw kind of chews into the plastic/tape, so a more permanent fix would be to glue some metal shin stock there. I also have an Orion EZ finder, and the elevation adjustment is stuck. So, once again I've been using bits of duct tape to shim the bottom of the EZ finder to align it with the scope. Overall, I still prefer the telrad.

Cheers
Mike Connelley

Hello:
Yes, you do. All star charts (even the ones the pros use) follow the convention that north is towards the top of the page and east is towards the left, which is the way the sky looks when you look up facing south. So, if you're facing south (in the northern hemisphere), then you do not need to rotate the chart. If you're facing north, then you'll probably have to hold the chart up-side-down. If you face west, the celestial pole is to your upper left, so you need to rotate the chart so that the top is to your upper left. The idea is to look at the sky, see which way the north celestial pole is for the part of the sky you're interested in, then turn the chart to match.

Cheers
Mike Connelley

Hello:
My guess, and it's just a guess, is that Meade tweaked the conical constants on the mirrors (and perhaps the figure on the corrector) so that the optical design is more like an RC or the new RX scopes. This wouldn't change the external appearnce of the scopes at all. It would presumably reduce the amount of coma seen in the scope, but field curvature would likely still remain.

Cheers
Mike Connelley

Hello:
I don't think you're doing anything wrong. I regularly get a LOT of dew on my scope and the mirrors when I bring it home. I observe from a high (9,300ft), dry, and cold (40F) site. I live in a low (600ft), warm(70F), and wet place. Thus, when my cold telescope meets the warm, moist air of our house, it's dew city! First, I wipe everything down with a cloth to prevent corrosion. I then use a blowdrier to slowly warm the mirror to get the dew off of the mirror by just blowing the drier into the front of the scope. Given that the mirror is over 2" thick, this can take a while. Once it looks like the dew is gone, I often have to blowdry it again 15 minutes. Blowdrying only warms the mirror face, whereas the whole hunk of glass is cold. I figure that condensed water plus dust in a moist environment is a recipie for mold, which I do not want on my mirror. I will also soon dehumidify the room where the scope lives.
So, I think the dew was on your mirror from the minute you brought it into your house. A wet telescope in a wet bag isn't doing itself any favors either. I would recommend towling the scope off if it's wet when you get home, and looking at the mirror before you put it away at home to see if there's dew on it. If so, then take a few minutes to blowdry it off. A few dirty spots on the mirror isn't a big deal. Most amateurs would probably be shocked to see how dirty observatory scope mirrors can get. If there's a lot of dust, it can affect the contrast of your scope, but in general it's better to just leave your mirror alone until it really starts to bug you.

Cheers
Mike Connelley

Hello:
The scope I mostly use these days is a 12.5" f/15 cassegrain, which in many respects is similar to your C14. As a wide field finder eyepiece, I recently got a 55mm plossl. For my main observing, I use a 31mm and 17mm Naglers. For planetary observing, I use plossls from 26mm to 12mm with a barlow. I really like the 31mm "grenade" for deep sky observing since it gives about as wide a field of view as is possible in a 2" eyepiece, yet also gives a high enough magnification (150x) to see real detail in galaxies. I use the 17mm in cases where I'd like more magnification. For deep sky observing, these two are about all I use, with the 31mm getting the bulk of the action. Both of these eyepieces have plenty of eyerelief, and I regularly observe with my glasses on. I haven't tried these with a barlow since the 17mm typically gives plenty of magnification for deep sky work.

Cheers
Mike Connelley

Hello:
If you're stacking images, the shortest exposure time you should use is one that gives an image where the sky noise (after you flat field) dominates over the read noise by some large number (5, 10, or whatever is your favorite). Whereas counts from the sky obey Poisson statistics and thus its noise can be beaten down by sqrt(n), dark noise does not and taken many more images to beat down to a similar level. So you should takes images long enough so that you're sky noise dominated. When this happens depends on your camera, filter, f/ratio, and probably a host of other things.

Cheers
Mike Connelley

Hello:
Televue already has these one some of thier eyepieces. I've seen several ~55mm Plossls where the eyepiece stops at the eye lens, so that you have to hold your head back a bit. In doing so, you can see around the eyepiece, and it's hard to hold your head steady in the right place. Several manufacturers, such as Televue and Meade, extend the eyepiece housing beyond the eye lens to prevent these problems. The 55mm Celestron eyepiece I have simply has a huge eyecup that also does the job.

Cheers
Mike Connelley

Hello:
I'm very sorry to hear that. It's snowing quite a lot about 30 miles from here, so they're not able to do much tonight, but the forecast says it's supposed to clear for this weekend. I do hope so, since I haven't been out with my scope since Novemnber.

Cheers
Mike Connelley
Hawaii (75F, raining cats and dogs)