Image of the day

Captured by
Lawrence Parchman

Sculptor Galaxy (NGC 253)

About Astromart

My Account

New to Astromart?

Register an account...

Need Help?

Posts Made By: Alex McConahay

March 9, 2003 01:44 AM Forum: Film Astrophotography - Imaging and Processing

Successful First Attempt at Prime Focus

Posted By Alex McConahay
Michael,

It is possible with a flatbed scanner if you have a slide adapter--which is not all that unusual. However, a dedicated scanner does a much better job.

Alex

March 24, 2003 02:08 PM Forum: Equipment Talk

Beginning accessories for C-9.25 SCT?

Posted By Alex McConahay
Verle,

Get a unit power finder like the Telrad or Rigel model. Then probably a good 10 x 50 or so finder if you are into starhopping.

After that, I think the field flattener.

I find the polar alignment scope useful, but not sure it is critical, since for the kind of observing you can do with a CG-5 does not rely on accurate polar alignment.

Of course, you will need eyepieces also.

And do not invest too much in that tripod. The CG-5, no matter how you upgrade it, is just not hefty enough for the 9.25. It works okay for visual.

Alex

April 1, 2003 02:23 PM Forum: Film Astrophotography - Imaging and Processing

Processing challenge

Posted By Alex McConahay
Maurice,

Go here

http://www.astropix.com/HTML/J_DIGIT/VIGNET.HTM

and when you are finished with that article, take a look t the rest of the site. It is the treasure trove of astrophoto technique.

Alex

April 4, 2003 02:55 PM Forum: Deep Sky Observing

Messier Marathon Musings

Posted By Alex McConahay
Hi all,

I got 74 of them last Saturday night. Straight starhopping. That was pretty good since I also took about two and a half hours starting at about 8:00 p.m. (and spread throughout the evening) to set up astrophotography with another scope. The biggest mistake I made was to set the dob up next to my trailer--which then blocked some of the early objects (including M31 and its buddies). I got M77--which I did not expect, and missed M74 in the early evening--and then set up the astrophotography. By the time I turned back to the marathon, I was staring at the trailer. Dumb Move.One of my buddies picked up 108 of the 110 Saturday. Starhopping with an equatorial mount. That was quite impressive. He missed 74, and then had a van parked in the wrong spot as the sun rose for the last object over in Capricorn.

Alex

April 13, 2003 11:00 PM Forum: CCD Imaging and Processing/Solar System

Help w/ ST4

Posted By Alex McConahay
Chris,

I went back and reread the article by Milan. It is good.

Did you take a dark frame? Was the temperature of the camera and the ambient temperature stable?

If you are getting CHANGING readings (with a covered ST-4), that may indicate the temperature is changing, either because the evening is getting cooler, or because the cooler in the camera has changed the camera's temperature.

If you are covered up and are getting unchanging non-zero readings that may indicate that the cap is not light-tight (hard to believe), or you forgot to subtract the random noise of the hot pixels that--i.e., you forgot the dark frame.

From your description of what happened, I would simply assume you either forgot to take the dark frame or the temperature was continuing to change after you took the dark frame. At any rate, just take another dark frame and continue climbing that old learning curve.

Alex

April 15, 2003 01:08 PM Forum: Home Observatories

Observatory Security

Posted By Alex McConahay
I'd suggest those lights on the outside be used with motion detectors. That way they come on only if somebody is around. If the lights are on when they should not be, people may notice. If they are always on, then people won't think anything special is happening (like vandalism). And besides, just because they are "Glarebusters" does not mean they should be on at night. The Glarebusting features reduce light pollution, but it is still there.

Alex

April 18, 2003 01:30 AM Forum: Deep Sky Observing

OT: Whirlpools in Space?

Posted By Alex McConahay
Darren,

From what I understand, there is pretty much the same amount of matter everywhere in a spiral galaxy. However, there is a pressure wave rolling around the spiral galaxy that causes the formation of bright new stars. Those bright new stars are visible, where the rest of the matter is not. That is why the galaxy looks like a spiral.

It is not as if the matter is really spiraling anywhere.

(Imagine the motion of a wave through water. The water may rise up and down, but it really does not move much laterally.)

Alex

April 21, 2003 03:02 AM Forum: Deep Sky Observing

Unable to starhop, setting circle help - newbie

Posted By Alex McConahay
Jay,

Analog setting circles do work--but not nearly as well as one would hope.

First off, be sure you are polar aligned. Doesn't have to be absolutely dead on as if you were taking astrophotos, but it should be as accurate as you can get.

Then set your circles to a known star. To start, point your tube directly at Polaris, and center it in the eyepiece. By the way, Polaris is not at O, O. It is at something else--89:15 d declination and 2 hours 31:50.

On most mounts, you will set your dec circle with a setscrew. Once you set your dec circle, you really should never need to change it again (assuming it is set with a screw or something). Most right ascension circles need to be reset on every observation.

Once you have Polaris set, go off to some other star you know for sure, and see how the circles change.

Try it for a while, you will work it out.

Alex

April 29, 2003 05:21 AM Forum: Equipment Talk

Telrad Reflex or Rigel Quickfinder?

Posted By Alex McConahay
I have both Quickfinder and Telrads (and the Televue Quickpoint--which I don't like)

I've always been a firm believer in Telrads. They seem to be easier to sight in. It is easier to line your head up, and the collimation (lineup with the main scope) seems to stay better.

On the other hand, They are way too big for what I need. I prefer the Quickfinder for the pulsing light, and for its size.

In short--I've always liked the Telrad, but I think from now on I'll go with Rigel's product.

Either one is great, but the Quickfinder fits in the eyepiece case better.

Alex

May 12, 2003 01:03 PM Forum: CCD Imaging and Processing/Solar System

Question: Focal length calculation

Posted By Alex McConahay

Ron,

Try

http://www.covingtoninnovations.com/astro/astrosoft.html

This free program helps calculate all types of exposure, including eyepiece projection.

Alex

Funding Member

Sponsors


View all sponsors

Search