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Messages - sdelbapaglo

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Reflectors Telescopes Forum / Re: What is that thing under your Dob?
« on: February 08, 2018, 06:28:25 PM »
Smart Alec answer: I think they're ALL less expensive than Tom O's gorgeous products. His have always been top-of-the-line.

I haven't looked on line for a long time since I'm out of the market for any more platforms. There are several brands that have been mentioned on CN that have had mixed reviews. One CN member (I can't remember Ed's last name) builds a few per year but you have to time your order just right to fit his outdoor build schedule. People really like his work.

Mounts Questions & Expirience / Re: Orion HDX110 EQ-G tracking issue
« on: February 04, 2018, 12:00:20 PM »
also I think your guiding at less focal length than your imaging and cone error comes to play in mount.

PA error has been ruled out by the lack of drift in the guiding logs. The LodestarX2 and guidescope is quite capable of guiding to arc second precision.

Weather interferes here too much for 'planning'. Blue Ridge Parkway's closed due to snow and ice, and almost surely will stay that way, so no access to good nearby observing site. But the sky's blue at the moment. _If_ it stays that way, I'll bundle up to watch the Geminids tonight. My folding reclining 'meteor shower watching' chair will be set up in the back yard, with a fleece blanket to go under me. I'll have a couple of low-power (nominal 1X & 2X), wide angle lenses ready to go for my Mod 3 night vision gadget. Looking forward to this, since it's my first coincidence of a major shower, clear skies, no moon, and my NVD.

Beyond that, no plans. It'll be 'take it as it comes'.

Jim H.

Beginners Forum / Re: Good eyepieces for beginner?
« on: February 03, 2018, 07:16:36 AM »
Nope, Jupiter is only white and I can barley make out the bands, and I mean barley.
The moon is extremely clear and crisp!
Not are what I am doing wrong.

I have an Orion 6" f/5...
You may have even seen flares coming off the planet, and induced by the telescope's secondary spider-vanes. The planet was too bright, probably. At least it was in my case. I attached a variable polariser to my eyepiece, to dim down the brightness a bit, then the flaring disappeared and I could see more detail and colours of the planet's surface...

You simply twist the two halves together and for different levels of brightness.

This is my variable polariser...

Beginners Forum / Re: Back at last! Need new telescope
« on: February 03, 2018, 02:37:06 AM »
An 8 inch SCT would be a good choice. Your primary interests are planets, moon and star clusters. Some general rules of thumb I believe in: a good four inch refractor should equal a good five inch reflector, but will not equal a good 8 inch reflector in providing detailed images of planets, or in its ability to resolve stellar points. When making these comparisons, collimation, ambient temperature for the optics, and quality figure of the optics are also important factors.

ATM, Optics and DIY Forum / Re: Comet shaped star in a refractor
« on: February 02, 2018, 10:27:37 PM »
Decentering an aplanatic lens doesn't produce coma as the lens has no field coma at least in the Seidel approximation.

It's certainly true for small decneter, Bruce, but here's the same refractor with a decenter in X axis of 5 mm/
As I said earlier, it takes a lot of decenter to bring this out, and it's very unlikely (even impossible) in a tight-fitting cell.


Beginners Forum / Re: Star Party frustration
« on: February 02, 2018, 05:04:41 PM »

Farmer White:

The advice to attend a star party is something I recommend for those who are unclear what they will be getting and seeing and seem to want clear answers, it's the safe approach.

Its also the approach few of us used.. It's like most of life, you have to get your feet wet. Finding the right scope, finding what you enjoy, it's a process, a journey of discovery.. You should not plan on your first scope being your last.. It should just give you an idea what this is all about..

A paraphrased story:

"Jon, you are an experienced amateur astronomer who has owned just about every type of scope out there. Should I just buy something and get myself started?"

Jon: "You should attend a club outing, a star party, find a friendly amateur, look at some scopes, look through some scopes."

"But that's not what you did, you just dove in."

Very true.. But I didn't have to ask...

Just do it..


Fear mongering has been used to control the people for most of history.Information control is an important  part-can't let people know there are other viewpoints!Many people are totally irrational about lights;back in 1986 while guarding a power plant,I turned off the  interior lights in the gatehouse in order to be able to see outside;almost at once the supervisor DEMANDED the light be turned back on,ensuring that I could not see anything outside further than a few feet! His concern was only that I was turning out the lights to sleep and explanation of the facts of light were ignored.Ever try to look outside into the darkness  from a very well-lit room ? I don't know whether to laugh or cry at the story of the astronomy group who  were told the city was planning to put up security lights at the observing site "for their safety ".

This might help, though there's no provision for electrical insulation. The hub could be made of Delrin though:http://www.raddobs.c.../wirespider.htm

Eyepieces Questions & Recommendations / Re: Masuyama 32mm 85 Deg
« on: January 31, 2018, 09:55:22 AM »
Masuyama 32mm in Orion f/4.7 XT10i with Paracorr I --

Tonight I decided to try it in my XT10. On same three targets plus on Pleiades. Best Paracorr-I setting was between mark 2 and 3 from the highest position. Most of the FC was dialed out here. The astigmatism off-axis was there, but when in-focus was only lightly noticeable. So the star points actually looked quite good in the far off-axis! I mean at 37x one is not going to get an airy disk from a 10" scope, so even the bright stars of M45 looked just great. And virtually all of M45 was in the FOV too, so that was nice. I'd say the astigmatism is discoverable (racking in/out of focus) at around 60% from center. But again it is minor there and well hidden in the star point at these low magnifications. When a bright star like Alnilam is at the field stop, so all the way out, it is just a little deformed by astigmatism with the deformation elongating the star maybe by 30% (mostly noticeable due to not being able to dial out all the FC). So not all that much when the Paracorr is in place (I did not try without it). Again, if one has their eye off best exit pupil position then the off-axis can appear worse, but when your eye is where it is supposed to be then was quite a clean view. Clean enough that I am definitely getting one of these for my Dob now! Quite a pleasurable eyepiece to use like I said, being rather compact for a 2" with comfortable ER. I totally did not expect it to work so well in the f/4.7.

Eyepieces Questions & Recommendations / Re: Delos 14mm vs Ethos 13mm
« on: January 31, 2018, 08:27:50 AM »
I went with the 13mm Ethos, I'm sure I'll be happy with it. Didn't quite have to take out a second mortgage lol.  I will be thinning out my orthos and a few other things to pay for it down the road.

Thanks again all

Excellent decision! I don't have experience with the 14mm Delos, but I've compared the 13mm Ethos to other excellent eyepieces in that range, including the 12mm Nagler T4, the 12.5mm Docter, and the 14mm Pentax, and the 13mm Ethos easily held its own in terms of on-axis sharpness and contrast. The 13mm Ethos handily wins of course in terms of FOV. I know that some prefer a narrower FOV for aesthetic and other reasons, but for me the greater FOV of the Ethos is not only more pleasing aesthetically, but also better for practical reasons. With 100 degrees, I can take in more DSO's with a large angular size, see more galaxies of a galaxy cluster in the same FOV, see more of the surrounding context of a DSO, and so on. And of course, finding objects and manual tracking is much easier too.

Beginners Forum / Re: Beginner Eyepiece Questions
« on: January 31, 2018, 05:07:26 AM »
Lots of good advice here, but also I'm sure confusing. As you can see, eye pieces are like cars...many great ones to choose from and everyone has their own particular favorite and style. I suggest keeping it simple for starting out. Just buy one, maybe two more eyepieces and a 2x short barlow. The following would work well:

32mm plossl = 47x, just over a degree of visible field of view and a 3.3mm exit pupil (this size of the light cone entering your eye). This size would make a good "finder eypiece" for setting up your scope and finding your target, as well as a fine low power eyepiece for larger targets such as open clusters, the Orion Nebula, etc.

Combined with the barlow your 32mm plossl would yield 94x, half a degree field of view and about a 1.6mm exit pupil. I find this size (16mm) to be just about optimal for observing most deep sky objects from my light polluted back yard and is also an excellent magnification for observing the positions of Jupiter's and Saturn's moons, observing the entire moon at once, etc.

Your exisiting 25mm ep = 60x, yields a field of view of 0.87 degrees and an exit pupil of 2.5mm. This is also an excellent choice for observing deep sky objects (though the sky background will be a bit gray if you have light pollution...but still very usable). It's also a good choice for observing the entire moon with a bit of dark sky surrounding it.

That same 25mm ep combined with the barlow = 120x, 0.43 degree field of view and a 1.25mm exit pupil. I find this magnification and exit pupil to be useful for observing smaller, brighter galaxies as well as being the magnification where planets begin to get interesting (more details visible). This would be the same as using a 12.5mm eye piece.

Your next eyepiece choice can vary...I'd go with anything in a range of 8 to 10mm. If you live in a region where your skies are often steady, I'd go with the lower end of that range. If your skies are more average, I'd stick with a 10mm.

For now, I'd stick with basic plossls. A decent set of plossls are very versatile eyepieces that can be used for a lifetime and with any other scope you may buy in the future. On the high end you can go with Televue, but the Meade 4000 series are also solid performers, as are the GSO's (which can also be found as Celestron Omni, OPT, TPO, etc).

Hope that helps a bit....oh, and don't be afraid to purchase an ep used. More often than not they will be in fine shape and you can always sell them later for about what you paid for's a great way to try different kinds of ep's to learn what kind works for you.


The reason I ask the question was primarily for new people to astronomy. I have talked with several new to astronomy and all they knew was the department storescope they bought and knew little else. I usually refer them to this forum or several books available at most library or maybe buying them if possible. It amazed me what they were told at different stores way out in left field. I my self give my vote to Dobsonians good bang for the buck. Thanks


Yes, I will agree that the Dobsonian-mounted Newtonian reflector offers the most aperture for the buck when it comes to observing DSOs. But I personally do NOT like the ergonomics of the design. It hurt my back to hunch over the typical 8 - 12 inch "Econodob" - or stand up all night with my old 15-inch Dob. Because I have gone through several spinal surgeries already, I'll pass. I am quite happy with the more comfortable (to me) viewing position of my refractor, MCT, and SCT designs.

For good reason, the standard 8-inch alt-az mounted SCT was the most popular selling scope for many years - maybe it still is. It's big enough to see things and comfortable to use.

As others have noted, the BEST scope is the one you want to use regularly. A Dob is not the one for me. YMMV.


I have the 8" SCT too, and I use it for narrow fields of view, but I'd use a 80/400 for viewing things like M31, large sprawling star clusters, etc.

ATM, Optics and DIY Forum / Re: Burch Null Test
« on: January 30, 2018, 02:34:45 PM »
Can a laser diode be used as the light source in place of the single mode fibre?

ATM, Optics and DIY Forum / Re: Finder scopes or red dot
« on: January 30, 2018, 07:40:17 AM »
I'm using my finder solely for getting acquainted with the region surrounding my target objects. Telrad's pointing performance is on par with-, or better compared to- some of the PushTo systems. The red dot was brought to astronomy from the guns world by merchants having no idea how to use a telescope (imho).

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