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Posts Made By: John Holt

April 21, 2008 02:58 AM Forum: ASTRONOMY

telescope for my 10 year old

Posted By John Holt

http://www.buytelescopes.com/product.asp?t=3&pid=11689&m=

May 17, 2008 11:33 PM Forum: Equipment Talk

RE: Orion 9x50 Correct Image Finder Mount

Posted By John Holt

<<
Thanks>>>

http://www.buytelescopes.com/product_list.asp?t=69

Anacortes has all kinds of option.

June 13, 2008 01:48 AM Forum: Solar System Observing

How many have seen Pluto?

Posted By John Holt

Peter Rice said:

Just wondered how many people have actually taken the time to hunt this one down. I've identified it several times using a 10" Cave and a 16" Nightsky and a star chart. Last Friday night, it was very close to a dim star allowing me to detect its motion over a few hours.

Other members of the club are surprised when I show it to them. Just wondered if many people in this forum have looked for it.

Pete

Yes, pretty easily in 13". But not recently. As with all else, detailed charting really really helps.

June 14, 2008 10:12 AM Forum: SCI-FI

Hottest SF characters/actors?

Posted By John Holt

Just saw Susan Oliver in a first season Twilight Zone from 1959, so several years before her green vixen gig in Star Trek. Very Nice!

June 16, 2008 01:46 AM Forum: ASTRONOMY

nebulae filter question

Posted By John Holt

scott staszak said:

I would like to get a set of filters for my zhumell 25x100 binoculars, some have advised they make a filter that will enhance nebulae and some clusters...is this true and which filter do I need? (zhumells have threads for filters) Thanks!


I'll take a stab at this.


First check this article out:
http://pages.sbcglobal.net/raycash/filters.htm

Next, IME a UHC type filter is a better match for a 100 mm or so scope. The OIII is pretty dark near this size.

This is the place to get the UHC:
http://www.buytelescopes.com/product.asp?t=48&pid=10169&m=


However, before buying two UHC filters for the bino's, and the ergonomics of threading them into it's ep's during observing, or perhaps now buying a matched set of ep's to mount them in beforehand- and then switching out filtered ep's.....

...anyway, it's a pretty expensive addition to do. An alternate consideration might be $200 more in portable aperture.





June 26, 2008 11:04 AM Forum: Eyepieces

Which is better?

Posted By John Holt

jack bitters said:

Which Eyepiece is better a K Or MA?
What do you think I have some of both and need to thin the Herd
Thanks
JB


An MA is a kind of K. Both are three element Kellners.
MA's are supposed to be an improvement over regular kellners, sometimes sporting a bit larger field of view. They are ok designs but really best suited to slower focal ratio's. Plossl's work significantly better with faster scopes IME.

June 29, 2008 01:48 PM Forum: Off Topic Discussions

Saving Gas?

Posted By John Holt

Paul Kammueller said:

OK I was wondering what others around here might have been doing to save gas since it's been $3-$4. I installed a mileage computer on my car which enabled me to fine tune my driving habits to the point where I was averaging 33-35mpg in mixed city/highway driving on a car that was rated 23mpg city, 32mpg highway under the old EPA measurement standards (21/29 on the new method). Now I've made the issue moot by switching to a job closer to home that requires less travel.

Anyone else doing such things? Anyone get a different car? Hypermiling? Biking or walking? Moving or changing jobs?


Slowed down.
I've been driving four cylinders of various sizes for many years. I learned along time ago that slowing down a little always improves the mileage significantly. Slowing down even more, and more often, does even more. That's not always practical. But to do so as often as is possible will yield better than published mpg on just about every car I've owned. Again, not all the time. (It's stupid to get in the fast lane for example and be a traffic liability) Slowing down it the original KISS method to less fill ups.

July 19, 2008 11:23 PM Forum: Deep Sky Observing

book on double stars

Posted By John Holt

tim wetherell said:

Hi everyone,

hope this is the right forum to ask this. Does anyone know of a book they could recommend on double stars? What I'm after is a book that lists the doubles in each constellation with their magnitudes and separations? Lots of books contain bits of this info but I've never seen one that had it all?

all the best

Tim


Online will have closer to it all.

Two book format are Burnhams (frequently available in the classifieds here) and Double Stars for Small Telescopes by Sissy Hass.

July 26, 2008 10:29 AM Forum: Eyepieces

Best value ~24mm wide for f5?

Posted By John Holt

Matt Tarlach said:

Hi there. I used to know more about this stuff but have been halfway out of the hobby for a few years now and out of date, I'm sure. I'm trading my little-used gee-whiz goto scope for a dob, in hopes of rekindling my enthusiasm for the hobby. No doubt the following is a common question but I don't have time to prowl the forums as I used so I hope some folks can take a moment to weigh in and help me out....

What eyepiece of those currently available would you all suggest to meet the following need:

- 1.25" barrel
- 65-70d degree apparent field
- 21-25mm (for ~max true field in 1.25")
- Good performance at f5 - center should be very sharp, edge acceptable. to give you an idea of my personal tastes I have a Meade 4000 24.5mm SWA that I find much too soft at the edge at f5.
- >17mm eye relief as I need to wear my specs at this exit pupil

Interested in two answers - 1) a top value eyepiece that does all of the above, and 2) the very best eyepiece to meet all these needs, in case the wife decides I deserve an early birthday present.

Any help would be much appreciated.

Matt Tarlach


Alternative plan B is a 32mm plossl.
Frequently available here in the classifieds for a modest +/- $30.
Fits most of the above performance criteria.
I like GSO's version.

July 27, 2008 09:20 PM Forum: Equipment Talk

S & T Recent Equipment Reviews

Posted By John Holt

Dave Sewell said:

I USED to really enjoy reading the S & T equipment reviews, especially back in the "good old days" when they would be BRUTALLY honest evaluating telescopic equipment - remember the 2 part SCT review or their evaluation of 10 inch mirrors? Those reviews also included a lot of impressive testing data too. NOW their reviews seem very "nebulus" to me - glossing over their findings and seemingly candy coating everything. For example - in the most recent issue - with the review of the StarBlast 6, all they really say is that the scope has 'good optics capable of delivering satisfying views'. But they only rated the optics 3 out of 5 stars and never disclosed why the mirror only deserved a 3 star rating. Same with the AT80EDT Refractor. Read the mini-review and everything sounds great, but once again - this scope ONLY gets 3 stars out of 5!? The review of the Orion imaging reflectors from a few issues ago followed the same pattern for the most part. I know, from personal experience, that quite a few of the Chinese made f/5 mirrors I've star tested displayed obvious turned edge. In their defense, the IN FOCUS views - at least with the 130mm size mirrors - were still very satisfying despite the defect. Just feel myself that it would be more enjoyable reading the reviews with FULL DISCLOSURE. How's everybody else feel about this? ...


With regard to the recent review of the 6" Starblast, they tested the mirror by just using it. They didn't actually bench test it. My own 6" f5 could benefit from a blower, multi speed focuser, Parracor and lord knows what else. This scope is a budget machine manufactured import unit. How many would they have to buy to get a broad enough sample to yield useable critical results? I think in this case the 3 out of 5 for optics can be read as equal to your findings of similar f/5's....very satisfying when in focus. : ) The "what we don't like" part of the review is right on target in my experience with my non-starblast. This size ota works best on a tripod. Period.