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Posts Made By: Renato Alessio

August 14, 2002 12:01 AM Forum: Equipment Talk

Re: 20x80 binocs or 7x50 or what???

Posted By Renato Alessio

Why the self restraint? Get two pairs.
Large, high power binoculars are great in their own right - but I rarely take mine out with my dob, when I prefer the smaller ones.
7X50s are best on the Milky Way in a dark sky. 10X50s are better on most other objects and sky conditions.
Renato

September 16, 2002 10:41 PM Forum: Equipment Talk

Problem getting Tide calculation software to run.

Posted By Renato Alessio

I downloaded a program that calculates tides anywhere on earth from
http://www.stargazing.net/AstroTips.

But when I run it in Windows XP, the black DOS screen comes up at quarter size, then it disappears, and that's it. And the same happens using previous Windows versions using the XP compatability option.

Has anybody else had this problem?
Renato

September 16, 2002 11:04 PM Forum: Equipment Talk

What I hate about most Refractors is.......

Posted By Renato Alessio

...... the dumb place they put their 6X30 finders, namely attached to their focusers. So unless an object is low in the sky, one has to crouch down very low to see into it, or raise the tripod legs very, very high.
After being driven nuts by this when I first got my Vixen, I fixed the problem by attaching a long flat piece of metal to the tube rings, and attaching another 6X30 finder to that metal. So I now have the original finder at the focuser, plus another one positioned on the metal bracket, such that it is up near the lens cell - which makes it very easy to use.
No one ever seems to raise this matter, which often makes a refractor very hard to use compared to other telescopes. Is it because everyone is more nimble and agile than me, in the way they bend over to see through finders?
Renato

December 2, 2002 09:43 PM Forum: CCD Imaging and Processing/Solar System

Nikon 4300 or Nikon 4500 or something else?

Posted By Renato Alessio

Does anybody have some advice on which of these two cameras I should consider getting, for general usage and mucking around with my telescope (planets and brighter DSOs)?

The 4300 has a bulb of up to 1 minute, and is up to ISO 400.
The 4500 has a bulb of up to 5 minutes, and is up to ISO 800.
Both have some noise elimination feature for long exposures.

I recollect reading here early this year that the previous models of these cameras required some extra gadget to get the higher bulb exposure times, and someone saying that the gadget shook the camera, making the long exposure useless. Is this still the case?

Do the differences in ISO make a difference?
Do the differences in bulb exposure time make a difference, or does the noise negate it?
The 4500 looks like it would be more awkward to use or more out of balance than the 4300, if it is attached to a telescope with a Scopetronix device. Is this correct or am I mistaken?

I would appreciate your advice, as the only thing I know about digital cameras is what I've read. I've only ever taken one shot with one. If you can advise me of something else to consider in the same price range or cheaper, please let me know. Thanks for your help.
Renato




July 17, 2003 06:18 PM Forum: Equipment Talk

Re: 3-steps is too many.

Posted By Renato Alessio

I just use the one step method on real newbies. I tell them to get an 80 or 90mm short tube refractor, and a copy of Bright Star Atlas because,
a. The 600 or so DSOs and hundreds of double stars would keep them busy for years,
b. If they grow bored with the hobby, this sort of telescope is still handy for terrestial viewing.
c. If they really get into the hobby and want a bigger telescope, the short tube refractor isn't made redundant. It will always be handy as a grab and go scope, and for its low power, wide field views.
Renato

August 14, 2002 12:14 AM Forum: Equipment Talk

Another filter question

Posted By Renato Alessio

The fairly cheap Lumicon Minus violet filter is advertised as giving pin point star images in refractive systems. Which it did, as well as giving me better nebula in my moderately light polluted skies.
Renato

September 1, 2002 11:26 PM Forum: Equipment Talk

Why "shorty" Barlows

Posted By Renato Alessio

Shorty Barlows are very handy for use with star diagonals, when you want to stick the Barlow into the diagonal (if you stick the diagonal into the Barlow, you get roughly 50% more magnification).

There's no other reason to have them, because the standard Barlows are otherwise superior. Shorty Barlows vignette the edges of the image when used with low power eyepieces.
Renato

September 2, 2002 08:34 PM Forum: Equipment Talk

Planetary Scopes

Posted By Renato Alessio

A 4" unobstructed aperture mask will get you close to the view of 4" APO - some of the time. Tube currents and an aberration (I forget which one) from the mirror prevent it being as good.

It only takes 15 minutes to make a sturdy aperture mask using tape and plastic from an art folder.

My 4" APO's superior contrast results in it showing somewhat more detail on planets than does my C8. But my 14" dob's superior resolution has occasionally shown more detail on Jupiter than anything else I've got. And the best planetary scope I've ever seen is a 10 dob a colleague assembled himself, using the most expensive components.

A 4" APO is a fun toy which delivers sharp star images and Airy discs (it's enjoyable splitting Antares). But personally, unless you're really into Airy discs, I'd work on sharpening up your dob first, perhaps by installing a fan to blow across the mirror, as described in S&T some six months ago.

Renato

September 10, 2002 12:38 AM Forum: Equipment Talk

First Filter?

Posted By Renato Alessio

I've got most of the visual filters, and I can only comment on visual use.
Deep Sky - a broad broadband, works best at a dark site. It enhances nebula, while hardly diminishing the stars. But I don't use it much.

SkyGlow - a broadband, I often use my 2" one in low power eyepieces at a dark site.

Celestron LPR - a narrow broadband, darkens stars more than the previous two, but is better on planetary nebulas - I've found 80% of the harder planetary nebulas using this one. It has also been the cheapest filter for a while.

Ultrablock - it darkens more than the Celestron LPR, and is probably the best for detail in most large nebula. It gives a more pleasing view than the O111.

O111 - The best for finding the difficult planetary nebulas.

If you're only going to get one, and you want to see planetary nebulas, you should consider the Celestron LPR. The only problem is that it becomes fairly redundant if you later decide to also get an Ultrablock or UHC. Getting two filters, a broad and narrow band, is the better way to go.
Renato

September 18, 2002 10:29 PM Forum: Equipment Talk

2.3x40 Russian Binocular ? why ?

Posted By Renato Alessio

I've got pairs of Russian 2.3X11 and 2.5X30 opera glasses, which are handy for constellations, and using behind a Telrad. Are your ones binoculars or opera glasses?

My old boss was always after a decent low power/ wide field pair of binoculars for hunting purposes.
Renato