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Messages - Trendsetters Branch

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ATM, Optics and DIY Forum / Re: Building a Foucault tester.
« on: February 09, 2018, 07:49:29 AM »
A focuser, never thought of it myself ...  In fact you don't need the whole focuser, just the Crayford-system will suffice.
On the other hand when measuring is done, the that testbench can be dismantled and the focuser can be used in the scope you just made.
...and as Danny did, a smartphone, never done before either.

If my phone was so smart why does autocorrect mess up so much. I hate everytime i write ke it turns it to me.

Beginners Forum / Re: What is the benefit of joining an Astronomy Club?
« on: February 09, 2018, 02:42:16 AM »
I joined the local club here in SJC mostly to get out of the house during my divorce phase two years ago :-)
The club has a great outreach program with star parties and access to dark sides which is here in Silicon Valley a rare thing. I like their lectures, with the star parties it gets a little bit stale when not having own equipment for observation and AP is not the right thing for parties. The parties are good thing to meet new people still and connect with the members. They have a lot of activity in the vicinity to SJC and connections to other clubs of different objectives but always coupled to astronomy.

TV Nagler 31mm for my Dob. Amazing EP!!

General Astronomy & Observing / Re: Name for new telescope? (vote)
« on: February 03, 2018, 03:51:28 AM »
If you like to live on the dangerous side, name it after an x-girlfriend. I am sure you and your wife will laugh and laugh and laugh over it.

Especially when he spends the night with it.

I've never been into naming my scopes but with the weather we've been having I'm leaning towards Overcaster I, Overcaster II, and the Cloudinator.


Beginners Forum / Re: Need my second scope already!
« on: February 02, 2018, 10:38:03 PM »
Interesting post discussion here.

I was curious, the question was asked earlier father&son, what 4" achro do you own. This is relevant, because not all 4" refractors have the same optical quality. So this is a question I have myself, if your budget is limited and the upgrade is to a larger aperture but lesser optical quality, is it worth the expense? Also I believe average seeing conditions and light pollution specific to your viewing site are important to know.

Really excited to see the responses.

ATM, Optics and DIY Forum / Re: Wood Finishing Experts Needed
« on: February 02, 2018, 05:17:53 PM »
Depending on what the piece is that has failed here, you could try a chemical paint stripper to see if it takes it off....
If it's a hand-made product, I'm leaning toward either a finish way past its shelf life, or as suggested, incompatibility between prime-coat and finish.
If it's a catalyzed-lacquer finish. I agree with DD that it was in some way bad, and you get the results. Cat-lac and ploywhatevers are unfortunately pretty hard to chemically strip..... and also agree to try lacquer thinner to see what happens. Lacquer thinner evaporates quickly, you could make a pad of several layers of paper towel and soak them, then attempt to scrape the hopefully softened finish off.
Best to do this outdoors, it's srong-smelling stuff better not inhaled, and the gloves-and-goggles rule applies, just to be safe.

Beginners Forum / Re: Am I the only one who
« on: February 02, 2018, 02:37:04 PM »
If I lived at a dark site I would probably store my 8" Evolution completely put together in our mini barn and carry it out assembled

Beginners Forum / Re: Why larger focal length implies more magnification?
« on: February 02, 2018, 01:26:50 PM »
I don't understand the direction of the blue and green rayes after the prime focus for both different stars (or object points), but I will get to it soon. They should not be changing directions, right?

Hi. At prime focus, the rays do not change direction, you are correct, since there is nothing there (just some air) to make them change direction. So in my drawing, they are not the continuation of each other, rather 'a new beginning' (no Star Wars pun intended). Tomorror I will make a ray tracing diagram more to scale, since I have a diagram somewhere I can use. Beer now!


Here in NW Houston we just passed the 2 day 20" rainfall mark. Forecast predict *another* 15-25"'. Yikes!

I wanted to spend this time working on my 25" scope but can't get to my storage unit.

thanks Alan - last night I got a reply from a professional Custom DOB builder who also told me about texas towers - appreciate the help from everyone

Mounts Questions & Expirience / Re: Fornax Lightrack II First light
« on: January 30, 2018, 01:44:53 PM »
Hi guys,

I sold my Astrotrac and got the Fornax lightrack. I will be testing it this weekend hopefully and I will let you know my results.

Here is is a picture of the setup which consists of the Fornax mount and wedge, Astrotrac head/counter weight system and polemaster adhered to the Astrotrac head.

Cheers!Attached Thumbnails

Reflectors Telescopes Forum / Re: Walter D150/F750 6" Newtonian Reflector
« on: January 30, 2018, 03:29:35 AM »
I'd believe them if they said that. I mean, if you get it, it's very easy to tell, so they wouldn't gain anything by saying it if not true.

Plus they quote a 750mm FL. And 750/150 = f/5.

And if you look at the tube in the photo, let's assume it's 7" in diameter to house the 6" mirror. Clearly, the tube length is roughly 4 times the diameter so that would give you a tube of at least 28". And that can house a 750mm (29.5) focal length, with compensation for the mirror adding length and the diagonal-focuser length subtracting from it. It looks about right to me as a straight through Newtonian without the Jones-Bird corrector.

The 18" package length must be a mistake or the tube is sectional.

My vote would be a 10" f6 using an optical window. I have thought about this a lot as I have been thinking of building one myself for my property out west. Always liked the size of the old Meade RG 10". For me f6 hits a sweet spot at 10", no paracor needed, enough FL to get to 30x per inch without a Barlow, and over 1.6 degree fov while having a secondary obstruction under 25 %.


I remember that and I also remember someone who built his pier onto a tree stump.
Bob G as I remember it, had a very large tree stump as a pier with a domed observatory (one of the first Explorodomes I think)
on top of it all.

Haven't heard from him in a long time.

Mounts Questions & Expirience / Re: CGX Mount Can't Find Home Position
« on: January 26, 2018, 01:26:14 AM »
I had a feeling I may have been too early jumping in on this mount. I should have waited longer.

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