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Posts Made By: Mike Ratcliff

October 4, 2006 12:50 AM Forum: Beginning Astronomy?

How's this one for you? Laser Collimation Problem.

Posted By Mike Ratcliff
One thing is that the UHC filter is not good on galaxies like M31. Blocks out too much starlight. The UHC and its cousins the OIII and H-beta filters allow only a few wavelengths through, and are designed for emission nebula that glow only in one or a few colors. (Note the colors mostly appear gray because they are too dim even with filters for our eyes to see the color.) If these filters are used on stars, clusters of stars, and galaxies, then you will lose a lot of light.

Edit: I don't have a laser collimator, but if you rotate the laser and things change as you rotate, the collimator itself needs adjusting. The laser is not lined up with the body of the collimator.

Mike

October 20, 2006 06:00 PM Forum: Reflectors

What is the best F ratio for a large newt?

Posted By Mike Ratcliff
Clive Milne has built a 20" f/5 binoscope.

Here is a starter link... http://www.binoscope.co.nz/clive.htm

describing his first light. (Bring the drool bucket with you. smile

Good luck!

November 10, 2006 09:32 PM Forum: Deep Sky Observing

What is your favorite EP for galaxy details?

Posted By Mike Ratcliff
An acquaintance of mine routinely uses 300x and more for faint galaxy groups, with a 20" dob. His main eyepiece for this is the 7mm Type 1 Nagler, that can be found on Astromart for reasonable prices used.

Myself, I don't have as much experience. But I am tending to use >100x much more often than I used to for finding details. My current main eyepieces (subject to change of course) are 20T2 Nagler (100x, 4.0mm exit pupil), 13T1 Nagler (150x, 2.6mm exit pupil), and 9T1 Nagler (220x, 1.8mm exit pupil) (16" f/4.9 dob)

The wide field helps in locating and hand-tracking.

I have a 9mm UO ortho that is a bit sharper than the 9T1 but loses big on FOV. The ortho is not used nearly as much.

Mike

November 15, 2006 06:43 PM Forum: Deep Sky Observing

Can you see these galactic details?

Posted By Mike Ratcliff
With a relatively new 16" in dark skies, the following are direct vision:
1. dust bands in M82
(edited since first version, I confused M81 and M82, dang needed some caffeine)
3. dust band 891
4. spiral arms M33
5. black eye M64
6. spiral arms M51
7. 604 in M33 along with several other nebula regions
11. spiral arms M101 (this varies from night to night, some nights the arms are more averted vision, I use this as an indicator of sky quality)
13. two dust bands M31, again a sky quality indicator

Only suspected:
20. bridge of M51

The others haven't viewed recently or noticed the feature or I have forgotten, I am terrible at notes too much work.

thanks for the questions.

Mike








November 28, 2006 01:06 AM Forum: Deep Sky Observing

To see Veil Nebula and North America.

Posted By Mike Ratcliff
The Veil Nebula does show some detail at higher magnifications, say 100X and greater. N. American nebula not so much detail. OIII filter is good for both.

Mike

December 20, 2006 05:07 PM Forum: Eyepieces

Celestron 99$ eypiece kit

Posted By Mike Ratcliff
Part of seeing detail is experience and time at the telescope. I'm doing more sketching these days just to help focus on what is there to see.

Undoubtedly, some people have very good vision, better than mine, as well.

And another factor is that high magnification can help see details, so seeing (turbulence) conditions could be more favorable on some nights allowing for more detail.

If you wanted to rule out the eyepieces, you could try an Ultrascopic, say the 20mm to 25mm size. It is not a widefield but is high quality. The Celestron kit is at least more of a bargain than the $300 Meade Series 4000 plossl kits that have been on Astromart from time to time. That is a ripoff.

Mike

January 22, 2007 06:40 PM Forum: Eyepieces

Naglers....what does it mean?

Posted By Mike Ratcliff
There is a good article at Cloudy Nights, "Nagler Mythos" I believe by Tom Trusock.

The short version:

Type 1 original, 13, 11, 9, 7, 4.8 (11 discontinued early due to 12 Type 2)

Type 2 redesign to reduce kidney beaning in the 13 and to go to longer focal lengths: 20, 16, 12


Type 3, no production ever released. Naglers' refuse to discuss, top secret. Some say it was to be the Radians. Some say military. Discuss at your peril.

Type 4, long eye relief versions: 22, 17, 12

Type 5, longer focal lengths, shorter eye relief, lighter than T2's: 31, 26, 20, 16

Type 6, shorter focal lengths, 12mm eye relief, much lighter and smaller for binos: 13, 11, 9, 7, ... down to 2.5 I think.

Types 4, 5, 6 are the only ones produced now.

One confusing part, some of the T1's started to be produced with eyeguards and knurled sides got to be called Type 2's but they aren't really.

Mike

January 25, 2007 09:19 PM Forum: Deep Sky Observing

Thermal issues and seeing

Posted By Mike Ratcliff
Part of it is that the jet stream is usually far to the north of the Florida Keys.

Here is a chart I look at. http://squall.sfsu.edu/gif/jetstream_init_00.gif

Today's chart doesn't look good for Florida, but does look good for me in S. California!

Mike

March 26, 2007 07:04 PM Forum: Deep Sky Observing

Messier Marathon - the Agony of the Realm

Posted By Mike Ratcliff
Here's one I use from Tony Cecce

http://www.seds.org/messier/xtra/12months/m-jun.html

One trick from there is a telrad shot half way between epsilon Virgo (brighter star near Rho) and Denebola (bright tail of Leo)lands on M84/M86 every time.

Lots of good general advice as well.

PS the monthly list is helpful in general.

Mike

July 1, 2007 12:32 AM Forum: Deep Sky Observing

Deep, deep sky catalog?

Posted By Mike Ratcliff
The Saguaro Astronomy Club has an Excel database with over 10,000 deep sky objects:

http://www.saguaroastro.org/content/downloads.htm

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