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Messages - Dan Perez

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ATM, Optics and DIY Forum / Re: Your Favorite ATM/DIY build?
« on: February 09, 2018, 09:17:42 AM »
Over a few years I have been completing my 20" carbon Fiber UL scope, it has been lots of work and time but I am so happy with how it has turned out. It is nice to be able to pick it up and move it outside by my self with out a cart and have it up and running in 5 minutes. I think I enjoy making telescopes as much as using them. My next project a 34" may end that joy for me. LOL

http://www.cloudynig...r/?hl= ctcablesAttached Thumbnails


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Well,

this is meant to be a beginner thread from a beginner to a beginner as I am pretty sure that everyone else already knows about these. I thought I would just share with new people what I found on my journey of just picking a telescope good for my own needs (still on-going at the time of writing).

3 main types of telescopes:

1.) Refractors: These are lense-based telescopes. Depending on quality of the telescope these contain anything between 2 and 6. Simple refractors suffer "purple-fringing" surround especially bright subjects (ak chromatic abberations) which are the result of different colors of the light spectrum being bent to different degrees. To fight this symptom, higher quality lenses were developed. Telescopes that have these lenses are called achromatic telescopes. More sophisticated setups contain various concave and convex lenses to focus different colors into one focal point again. These sorts of telescopes are called apochromatic telescopes. Because these telescopes contain many lenses with many surfaces, that each have to be finely crafted, they are the most expensive. Prices increase quickly...and for these telescopes it is not too uncommon to see prices as high as 10K for a moderately sized siystem (5-6").

To get started though, one does not need to pay exorbitant amounts. Here are a few (mostly achromatic) telescopes:

- 102mm Achromatic Refractor: 4" telescope with good wide field of vision. I have seen sale prices as low as $399 for the OTA only.
- 127mm Achromatic Refractor: 5" telescope with better light capture then the model above. Normal prices are around $599.

I have read many good reviews. Good price for quality achieved. Of course, at these prices you are not going to fully eliminate purple-finging, but it should not be very noticeable with these achromats. Bigger sizes are also available, but they, in my opinion start getting unwieldly large. Smaller sizes are going to be cheaper of course, but for those you will be limited to brighter objects (such as planets, and the really brightest and biggest nebulas and DSOs)

2.) Reflectors: These are "mirror-based" telescopes. Instead of lenses, mirrors are used to bundle the light. They are MUCH cheaper because, instead of polishing 4-12 surfaces, one only needs to do a good job on the primary mirror (1 surface). It's common wisdom that in terms of bang for the bug, this is where you will likely find it. I personally have been exploring 5" newtonians on a Go-To mount, and found that basically, the OTA is the same piece of equipment in each of them. Examples below:

- Celestron Skyprodigy 130:
- Celstron 130 SLT: The link to this is actually a review meaning to show that despite the concerns below, people can be happy with these sorts of systems.
- Orion Starseeker IV 130:

People on these forums will quickly point out that there are several issues with these scopes. Despite great optics of the mirror, these scopes come on very undermounted tripods - at least the Skyprodigy and SLT system. I can attest to that as I looked at the tripods for the first 2 models. I have yet to see the Starseeker IV tripod. It appears to be more solid and might be acceptable actually. The other piece I WAS able to confirm though is that the Celestron telescopes mentioned above have a plasticy looking focuser piece.
People on the forum say that these focusers will prevent great accuracy at higher (~200x) magnifications. Again, I have not been able to confirm this for the Orion model.

When I was in 2 different stores, I found it kind of interesting: Newtonians below 6" were made in the cheapest possible way. Most were afflicted by the above type problem. I could not find well-built telescopes below 6". If the community or searcher did find Newtonians of this sort do point it out! What I found instead was that 6" somehow represents the magic boundary for for well-built Newtonians with solid tripods (of course, one buy tripod/mount and ota separately but somehow this is less cost effective). I don't know why that is, but one outstanding example I think is the below:

- Celestron Advanced VX 6" Newtonian: Comes with the well-built Celestron VX GoTo EQ mount (by itself this costs $799 when not on sale), and Celestron's 6" Newtonian (by itself $299). You will save $100 when you buy the bundle as the bundle cost is $899 when not onsale.
- Celestron XLT 150 OTA: This is the telescope only. Great optics. Great mechanics, too! You will notice 150mm = 6" roughly.

3.) Catadioptric telescopes use both (a corrector) lense and a mirror. In terms of pricing, it is common wisdom that these are between reflectors and refractors in terms of price. This is also where it gets a bit more complicated. There are 2 common types of catadioptric telescopes. The so-called "Cassagrain" design uses a corrector lense in the front, a primary mirror in the back, and a secondary mirror in the front where the corrector is to reflect the light back to the back of the telescope. This light-folding pattern leads to very compact OTAs.The 2 flavors are Schmidt-Cassegrain and Maksutov-Cassegrain. The main difference between these 2 scopes are that in the case of the mak telescope, the corrector is a meniscus type lense, and the secondary mirror is just the silvered central part of the meniscus lense. It is said that the smaller obstruction in mak telescopes leads to better contrast at the cost of more magnication/but smaller fields of view. Walking into a telescope store, and online, the potential buyer will quickly come across the Celestron NexStar or Evolution Series. These are the models I looked at from a very beginnery point of view. Obviously, the more money you have the larger you would want to go (up to 8" in my opinion). I will only list the Nexstar versions here as they are more cost-effective. But if you like very techie products with things such as local wifi, phone and tablet control features etc, look to the Evolution series. Be aware though these features will likely cost you at least $200 more compared to an equivalently sized Nextstar model.

Celestron Series (below are the models I was mostly considering for costs and portability):
- Celestron Nexstar 4SE
- Celestron Nexstar 5SE
- Celestron Nexstar 6SE

Orion sells Maks:
- Orion Starseeker IV 127mm

There is some discussion going on as to the FoVs of these telescopes. Fact: The FoVs will be narrower than comparable Newtonains or refractors. This is the reason why all these systems mostly come on computerized mounts: with narrow FoVs, a new beginner would quickly lose patience finding objects without computer help. The open question is: With computer aid, are narrow fields of visions a drawback. There is a different thread for this discussion. In this thread, I am just raising this as a point the potential buyer should be aware of.

In my search what I found most surprising was that there are other variants as well, things like: Maksutov-Newtonian, or Schmidt-Newtonian. You will guess from the name that these scopes are essentially newtonian telescopes with either the Schmidt or Mak version of a corrector. Their main advantages are that these plates can correct for "aspherical abberations" very well - something standard, larger Newtonians are prone to. An example of that sort of scope can be found below:

- 152 Comet Hunter Maksutov-Newtonian: 6" OTA. Cost when not on sale $699. You will need to buy a solid tripod/mount to go with this OTA. Since I want a GoTo mount, I would have to consider the VX mount which runs another $799. For a beginner, I feel that this is pushing the outer boundaries of initial costs. The upside is that this scope + proper mount would last a long time.

I will end this post by pointing out that in addition to the scope, one should plan in a budget to buy at least 1-2 additional good quality eye pieces and a barlow lense. This last statemen in itself could be a whole new chapter of discussion. But since this post is already pretty long, I will keep it short and end it here.

Anyway, this is not the end-all, be-all guide, but perhaps this sharing of what I have found so far will be useful to other new community members also on the hunt for the holy scope :-)

Cheers!

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Optics Mart is (going) out of business.

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General Astronomy & Observing / Re: How do Amature Astronomers Earn Money?
« on: February 08, 2018, 09:48:08 PM »
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Hello Cloudy Nights!
I was wondering if anyone has heard of any ways an amature astronomer can earn money.
Has anyone had any success earning anything?
Thanks you!

make youtube videos, you may be able to make some money per month if you let them place ads on your vids.

you never know what will bring a hit so don't let your mind stop your imagination.

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ATM, Optics and DIY Forum / Re: and another one bites the dust
« on: February 08, 2018, 08:30:22 PM »
"and another one bites the dust"

The title implies that there was at least one more piece of glass/quartz that hit the floor at some time in the past.

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Dan,
Hi, me again--the guy who's default location was off on your map somewhat. I found that I am running IE Version 11 (to be precise 11.953.14393.0)!, if that helps any, and again OS is W10. Hope that helps you some in figuring out why my location is off. Thanks again Dan--I'll check back this evening and then every other day or so to see if it's working any better for me.
Take care, clear skies!
-jim-

Thanks Jim, I've got the same version on my laptop so I'll do some investigation over the next few days and see what I find. Thanks again for the report

-Dan

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I'd seriously consider a 120-127mm apo for your stated intentions, probably the Skywatcher 120ED. It may not have the ultimate performance of other scopes mentioned above but it will be no fuss (no collimation, dew, mirror shift, cool down etc) and provide excellent views of thousands of objects. Put it on an AVX-class mount for tracking/go to and later get a manual alt-az for quick looks.

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Tracking will still only be in RA, so if you are ridiculously off in PA, the object will eventually drift out of the eyepiece. However, the mount will know the polar misalignment from your 2+4 model, so the GoTo's will remain intact. For instance, if you had a poor PA and observed Jupiter until it drifted out of the field of view, if you hit GoTo Jupiter again, it would put it right back in the center. Basically, even though the tracking isn't perfect, the scope will know where it is and be able to provide good GoTo performance.

Not necessarily. I know that SkySafari (at least when used with the SkyPortal dongle) allows you to select tracking in declination as well.
Is this done within SkySafari ?

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Beginners Forum / Re: I got a negative response from the local club
« on: February 03, 2018, 06:30:01 AM »
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Den25,

Now that you are part of the family we look forward to sharing the sky with you. 

I hope so. Where I live I've noticed I have more light pollution than I thought. I live near downtown. I'll be needing advice on that as well.

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General Astronomy & Observing / Re: Observe planets and Moon.
« on: February 02, 2018, 06:14:03 PM »
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One could say, then, that in order of importance and in relation to planetary observation would be ....:
-The quality of the mirrors
-The focal length (in this case the more the better ..)
- The aperture of the telescope
I imagine, that the collimation and the proper cooldown are very important factors that are above the three characteristics mentioned above ..
Regards,

I would rank aperture first, assuming good quality of optics, then quality of optics, and then focal length last, but it needs to be a practical focal length. Collimation and thermal factors are variables, usually under the control of the telescope's operator.

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Reflectors Telescopes Forum / Re: Boundary Layer Fan Install
« on: February 02, 2018, 02:38:25 PM »
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I’d love be to hear your opinion of using the fans vs not having them. Do you notice a small difference, noticeable difference, or “oh my goodness how have I ever gone without” difference.
Also curious to hear about Allan Wade’s system in use.
Ryan


Ryan,

The deal is this:

The majority of active cooling (for me) is the fan blowing on the back of the mirror. That's about a 65 percent improvement on cold night's. On summer night's it's all I need because the mirror is already close to outside temps. The boundary fan on January night's adds about 35% improvement making it a full 100.

What's "improvement"?

Best examples are the smaller objects, Galilean moons, a small mars. Normally there is flaring on these tiny discs which for years I attributed to seeing. And SOME of it was. What I had no idea was how much those spiking flares and such were RETRACTED by the primary fan. The flares not only appreciably shortened, but also lost brightness appearing more transparent. There still is flaring now (assuming January temps) and on deeply, you might never care. On doublestars, minute planetary features, miniscule lunar rills and tiny moons, the boundary fan makes a marked improvement. It's absolutely real.

Looking back on it, I can't fathom why in he'll active cooling isn't standard on all reflectors. Maybe some folks just don't care. Don't forget, a lot of reflector users from big to small like using between 50x and 120x , low mags where the notion of improvement might never arise. Even here its noticeable when active coolong is used, but if you re the casual kind, you might not care.

For me, now, it's the ONLY way.

Pete
I agree.

Extended DSO's, when viewed at low power, will show no improvement with the fans on. Small DSO's at high powers, think planetaries, will start to show improvement. A secondary effect of the fans is they help to prevent dew on the primary.

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Beginners Forum / Re: Hello all, New member and first time solar question
« on: February 02, 2018, 01:30:37 PM »
PST and the Sun will not disappoint you.Later you will be able to buy an upgrade - doublestack, and, even, to increase the aperture.

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I kept ramping up the power in my Mak, wondering why I couldn't see Saturn's rings...... Swapped the 32 plossl for the 25, then the 17, then the 10... where have they gone?? has the planet suddenly tilted so the rings are flat? The seeing can't be THAT bad, can it?......I was looking at Antares. Took me a good 5 minutes to realize. What can I say, I'm a genius

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ATM, Optics and DIY Forum / Re: Delmarva Mirror Making Seminar
« on: January 31, 2018, 04:21:20 AM »
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I suspect most "students" who attend Delmarva arrive at the workshop with no material and simply begin on the pre-curve-generated blanks and tools ordered and supplied at the workshop.
its all over the place on that.

I like to show up with something mostly polished out at least.

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A Mak or SCT would probably be ideal due to their short length, as the eyepiece doesn't move much, but you'd have to settle for less aperture. If you found an old C8 that doesn't have goto it would be cheaper AND have less electronics to deal with. And would be lighter, too.

Edit: but if on a wedge that could result in difficult viewing for certain areas of the sky, so that would have to be considered too.

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