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Messages - trapoutampub

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Oh, that's for the equatorial mount. Missed that fact.

Mounts Questions & Expirience / Re: Problems with GOTO mounts
« on: February 09, 2018, 05:29:40 AM »

John Cameron had one of these buggers and he did a good review with a potential firmware upgrade to fix the issues with this AZ mount. Do a content search on his name there were more than one article I think. HTH!


Beginners Forum / Re: Another newbie eyepiece question
« on: February 08, 2018, 10:19:58 PM »
Dark White? Isn't that grey?

Reflectors Telescopes Forum / Re: Ebony Star Azimuth Kits...
« on: February 08, 2018, 12:10:47 AM »
Has anyone ever tried textured paint to achieve the pebbly finish? Several clacker-can brands make that faux-stone look paint that leaves a hard, pebbly finish...


Beginners Forum / Re: Battle of the 8" mass-produced dobsonians
« on: February 04, 2018, 11:40:03 AM »

<p class="citation">QuoteOrion XT Classics are out becaise I don't like their spring mechanism.


Have you ever actually used a scope with "correction tension springs?"

Of all the systems on commercial Dobs, it's my favorite, it mimicks the large altitude bearings of the premium Dobs. My 14 year old GSO Dob uses the system.. I use it at magnifications up to 822x with good results..


No, I haven't. I've only used Zhumell altitude bearings on a mini-dob (Z114).
I have, and I found them to be horrible!
Another vote for the Z8 from me. I had one of these, and it was almost great right out of the box. With all of these scopes, you'll need to replace the primary springs. As mentioned, the knob is no big deal, and you can build your own dustcap.

Beginners Forum / Re: I would like some advice on my 40mm refractor
« on: February 03, 2018, 11:39:15 AM »
Den, when I have a bad week, focusing on the sky, even if only naked eye, really helps... I can put all that bad stuff away for a while and just relax a bit.... of course, the sky has to cooperate...

Best regards!


For all, here is a link that I read before buying my two Celestron 2" Ultima LX 22mm &amp; 32mm Lenses.



Mounts Questions & Expirience / Re: Integrated WiFi - The Future?
« on: February 02, 2018, 07:08:56 PM »
I have a car power unit with two standard 12v sockets and a USB socket that I use to power my kit in the field, the USB socket will also double as an emergency power source for my iPhone and iPad. Of course there’s also the power socket in the car.

Light Pollution Topics / Re: Open Air art project in Philadelphia
« on: February 02, 2018, 04:36:25 PM »
All for one and one for all. Just taking a moment to spend time doing worthwhile stuff! Thanks, csa/montana, fred1, barasits, Tonk, and everyone else! Dark Sky Scott, IDA, BRAVO!Best, Tom

So I went ahead and took a few scans of stacked filters, and sure enough, you simply get merging of the passbands. It felt good to validate a hypothesis, that doesn't happen much in actual science

Here is a #12 Yellow + #58A Green. This is the closest I could come to what we talked about above since I don't have a #15 Lt Orange.
As you can see, you get pretty much the exact same curve as what I diagrammed earlier today. You simply integrate the two curves and that's your new transmission curve.

The same holds for a #12 Yellow + #80A Blue combo.
But you'll notice the tail transmission dropped some as well. This makes perfect sense though. The #12 transmits 90% in that range, and the #80A around 82%, so 0.9*0.82 = 0.74, which is exactly what the combined filters transmit.. 74%. This isn't as evident in the above combo because 90% of 10-20% is still pretty much 10-20%.

And lastly, I combined a #12 Yellow with a #21 Orange, and as you would expect, all you get is another #21 Orange, but with slightly lower transmission due to multiple 10% losses.
So if you're ever wondering what your new transmission profile is when stacking filters, just integrate the two curves and multiply your transmission losses. That'll be your new transmission curve

Reflectors Telescopes Forum / Re: Most "convenient" 12-14 inch scope?
« on: January 31, 2018, 09:13:16 AM »
Most 10" dobs will fit across a back seat. I don't think many vehicles could hold a 12" OTA sideways. I'll measure.

ATM, Optics and DIY Forum / Re: Making a Mak Newt or a Houghton Newt?
« on: January 31, 2018, 07:53:11 AM »
Yeah, Mangin mirrors bother me for just that reason. If you are looking for a high contrast, high performance surface, a Mangin mirror is the worst of the worst when it comes to sensitivity to surface "smoothness", not to mention actual overall surface accuracy.

And given that surface "smoothness" is hard to quantify..that gives the OCD engineer type in me pause...I just have visions of mild "dog bisquit" ruining an otherwise top notch optical design.

Beginners Forum / Re: First Scope / Refractor Advice
« on: January 31, 2018, 06:43:37 AM »
I'm looking to buy my first serious astronomy telescope. Of key importance to me is portability, not so much on a plane, but being able to throw it in a car and take it to locations such as Tahoe and Monterey CA, which generally should have better viewing opportunities than my native San Francisco Bay Area.
How big is the car, and how many other people would be traveling with you? Almost any plausible beginner scope is trivial to toss into a normal car's back seat. In particular, this is easy to do with the standard beginner recommendation, namely an 8- or 10-inch Dob. Also easy with an 8- or 10-inch SCT or most moderate-sized refractors, especially if they're on alt-az mounts of some kind.

<p class="citation">Quote
In reading many reviews, a refractor seems like a good choice. Not the most cost-effective, but again, way more portable than a standard starter dob or other larger aperture piece of equipment.
I wouldn't phrase it quite like that. I would argue that per unit of performance, refractors are the least portable of all designs. That's because they have relatively long tubes with the eyepiece at the bottom. That, in turn, means that you need an unusually tall and heavy mount. And for all telescopes except Dobs, the mount is the least portable component of the rig taken as a whole.

Insofar as refractors are more portable than (say) Dobs, it's because they tend to be much smaller -- and therefore also have less light grasp and resolution. The distinction that you're making is really between small scopes and medium-sized scopes, not between different designs. And it is true beyond doubt that in the world of small scopes, refractors reign supreme as long as money is no object.

<p class="citation">Quote
I've been looking as a SW proED 120 or ES 127 CF. Basically, my thought was getting the most bang for my buck for aperature relative to weight. A 5" scope seemed to be a good trade-off in this regard.
That's a fair statement. A 5-inch APO is a pretty serious instrument -- quite a big jump from a 4-incher both for planetary and deep-sky viewing.
Note, however, that both of the scopes you have listed are fairly heavy, and have fairly long tubes. That means they need big, heavy, expensive mounts to perform anywhere near their potential. Taking the rig as a whole, my guess is that you'd end up with something intermediate in portability between an 8-inch and 10-inch Dob.

<p class="citation">Quote
That at being said, I've also started to consider getting a 100mm scope from either SV or Williams, that would likely have much better optics versus the 120s considering, but still be light, since it's a smaller scope. ...
Does anyone have any relevant thoughts on what I'm generally considering, as well as the trade-off of a larger 120ish scope versus a smaller, but better quality one?
In the price range you're considering, differences in quality are pretty small. You're solidly in the realm of diminishing returns, talking about the difference between a very good scope and a great scope.
A very good 120-mm refractor shows far, far more than a great 100-mm refractor.
Having said that, there is something to be said for starting small. If you were stuck with one telescope for life, the 5-inch APO would be a no-brainer.
But if you're planning to add a real telescope to your collection (real being the opposite of refractor  ), then a 4-inch refractor would arguably be a better complement to the bigger scope.

I started with a 70-mm refractor before adding a 7-inch Dob to my collection, and I have never regretted that decision.

Beginners Forum / Re: Hello from the D
« on: January 30, 2018, 12:21:34 AM »
One handy thing Bought years ago is a roll up table, great for putting all the gear on, the legs unscrew and in rolls up about the size of the c6 tube.

Wide field certainly isn't necessary for planetary viewing, but my 17mm ES92 is my favorite planetary eyepiece.

I would love to see one of those on a C6!

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