Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - James Pederson

Pages: [1] 2 3 ... 8
<p class="citation">QuoteRight now I am looking at either an iOptron IEQ45 Pro or a Skywatcher EQ6-R Pro, and both are just a smidge above your budget, but both would be a bit heavy for carrying up and down each time I'd think.

That is very interesting to hear. Thank you. Does the 1-star alignment include "one star nowhere near Polaris"? And does that make the alignment accurate enough for astrophotography?
My current main setup is a micro four-thirds camera with a legacy 180mm prime lens that, with my camera's crop factor, is effectively a 360mm lens. It would be nice to be able to go to twice or maybe three times that. I'd eventually like to upgrade to an actual imaging scope, like a William 71 or similar. Something in the 300-500mm focal length range (= 600-1000mm effective, with my camera). So you think the CEM25P would be able to handle that?

And yeah, I've also been thinking about a iOptron IEQ45 Pro or a Skywatcher EQ6-R Pro, but just as you say, they're slightly outside my budget range and would be a bit heavy to schlep up and down the stairs.
You can do a "polar align" with stars away from Polaris in the hand controller, then do a 1 star align after you do your polar align on another star near your target. They are 2 different things, but I am running 1624mm FL unguided on my ZEQ25, which is the predecessor to the CEM25 and after I polar align (though I do it through the polar scope in a normal way since I see Polaris) I then do the 1 star align and generally can put everything on that side of the meridian within the center 25% of my 8RC. When I use it with my AT65Q (420mm fl) I can run it unguided for a few minutes and get decent results with an APSC or FF camera. I wouldn't even hesitate to run it with a 102mm triplet with flattener. A refractor in the 65-80mm would be excellent on this mount.

Tonk, I'm sorry to hear you fell into your pier excavation, but looking at your avatar, I guess you're well prepared for such eventualities. Try digging deeper, it's bound to go eventually! Joe

ATM, Optics and DIY Forum / Re: Making an 8" Dall-Kirkham
« on: February 02, 2018, 07:58:31 PM »
Autocollimation might be hard even if you had a flat because of the two unaluminised glass reflections but you have the quality Space Conqueror although sub-aperture to produce a collimated beam.

Now that's an idea!

Any comments on the design?

ATM, Optics and DIY Forum / Re: Autostigmatic Microscope (ASM)
« on: January 31, 2018, 12:54:29 PM »
Of course, an infinity corrected MO requires and additional lens -- a microscope tube lens -- which are not cheap, not even on eBay. ASM's with a 160/170 mm conjugate objective is much simpler, requiring no more than surplus beam splitter and an eyepiece.

What's special about the tube lens ?

Beginners Forum / Re: Getting more color and detail from scope
« on: January 31, 2018, 10:22:02 AM »
Tony has anticipated my reply to the principal question concerning the matter of improved performance by upgrading to better eyepieces. It's subtle. On axis, a half decent eyepiece leaves little to a premium one. Atmospheric conditions, objective quality and one's own eye make for far more variability. But where better eyepieces can make for notably improved performance is in the outer field, and/or by offering a larger apparent FoV (and hence true FoV at given magnification.)

As to color detection when dark adapted. While dark adaption brings to the fore the action of the non color discriminating rods in the retina, this does not 'disable' the cones. One can still perceive color in an object whose surface brightness is sufficiently high while simultaneously being well dark adapted and glimpsing the very subtle, dim stuff. But where the brighter, colorful object falls upon the retina will cause that region to have dark adaption at least somewhat impaired.

This is correct. The cones are not disabled with the lack of light, it is the opposite though that the rods are disabled in the presence of bright light, that is why we use red flashlights to preserve our night vision. Also the reason we need to use averted vision is because there are no rods in the center focal point of the retina, only cones there. Just off center of vision though the rods, once dark adapted will provide superb black and white vision. In the absence of light a chemical builds up in the rods that helps them become more sensitive to light, when bright light hits them this chemical is destroyed, that is what you feel when you suddenly turn on bright lights when your eyes are dark adapted, not just the iris contracting in response. The eyes are most sensitive to green light, that is why you see green in the Orion nebula, blues are second most and red is least sensitive. It is also a reason most instrument clusters in vehicles are green lit.

An example of being able to see color in the dark is walking into a dark room at night after you just awake and you are able to easily see the red led on the tv from all the way down the hallway. The center of the retina has more cones and you see the led easily in center of vision, even in daylight, your side vision will be less colorful because there are more rods and fewer cones in that part of the retina.

ATM, Optics and DIY Forum / Re: Another Star Test.
« on: January 31, 2018, 07:11:54 AM »
I can read ten posts or more and not have a clue what was said except to know there is a difference of opinion

Ditto here, Joe! It doesn't matter how many years you put into something there's always going to be something you don't know, or someone who knows what you don't. Just keeping up with the latest is enough to keep you busy. So, humility is always in order. Even the top scientists disagree on a number of issues. That's the beauty of science.

Beginners Forum / Re: Grrrr!...Can't believe I did that!
« on: January 31, 2018, 05:03:40 AM »
My whole telescope tripod and weight driven clock drive fell to the ground 8 months ago. I suppose I was lucky because it fell on me instead of the cement patio. The scope had no damage but I was messed up since the complete thing weighs 200 lbs. The only part that had damage was the leg of the tripod which I replaced. I have a clock drive like the Unitron drive and It never touched the ground. I was sweating bullets when this happened.

Beginners Forum / Re: Question about eyeglasses and viewing
« on: January 31, 2018, 04:36:00 AM »
There is something to the motion. I trick I read about, and use regularly on Jupiter, is to pull my head back quickly from the EP. There is something (don't ask me to explain) in the brain that activates which sharpens your vision when you pull away. Something evolutionary which makes your brain think you are trying to avoid something coming at you. The instant you pull away you get a sharper image.

I'll see if I can find the article I read about it and will post if I do.


ATM, Optics and DIY Forum / Re: Foucault confusion!
« on: January 31, 2018, 01:12:19 AM »

Its suppose to be a sphere, but it has a big **** hill in the middle. And a bad tde

Thats a horrible vid to show anyone starting out.

Maybe... But if that has a TDE, then I think I have a TDE.  No hill though, which probably doesn't matter if I have a TDE.

dark shadow on one side bright ring on the other, either a tde or tdu. depends on which side the ke is compared to the shadow.

it all matters. if your not fully polished to the edge I wouldn't worry about it.

ke takes practice.


General Astronomy & Observing / Re: Next maximum for Mira in Dec '17
« on: January 30, 2018, 11:51:21 PM »
I think I read somewhere the "Mira" Sorvino was named by her Father for this star, - and I just assumed "Miramax" movie's got their name from it's variable status. Probably wrong on both counts.

The given name of Mira was in common usage ages before the discovery of the variable star of the same appellation. Although carrying various meanings in different languages, its most common interpretation in more modern times is "the wonderful" or simply "wonderful" and thus appropriate as a female given name. The variable star was basically given the name for the same reason that parents might name their beloved baby girl the same appellation. So, most situations in which it makes it appearance today are simply coincidental to the naming of the variable.


So, you (all) would say that "you get what you pay for"?
Therefore, like anything else, buy new if you can (new-ish, if you can't), stay away from cheap chinese knock offs?

I suspect that, dollar for dollar, one brand is (typically) as good as another, but what brands would you particularly steer clear of? Which brands are still using outdated deposition techniques?

The previous description of "delamination" (peeling?) startled me. My thought was that the biggest killer of filters would be fading of colors, being exposed to light and (most especially) weather.

I used the 7.4mm earlier this month viewing the first quarter moon along with some orthos. The 7.4 has great optics, but is definitely eyelash territory for me.

ATM, Optics and DIY Forum / Re: Intstalling WiFi on an Orion Intelliscope
« on: January 30, 2018, 12:30:01 AM »
Here are my settings in Sky SafariAttached Thumbnails

Mounts Questions & Expirience / Re: Sky Watcher EQ6-R small review
« on: January 26, 2018, 08:43:24 AM »
I had mine only for tests and evaluation, so I did not make many pictures
Here is the link to higher resolution M35 image obtained with EQ6-R

This picture is fantastic.

Beginners Forum / Re: Beginner Eyepieces for Dobsonian
« on: January 26, 2018, 02:17:44 AM »
Welcome to CN and enjoy the scope. You'll soon discover many new sites.

When I purchased my 10" dob i decided to get quality EPs i would use forever. I decided on wide field EPs because I enjoy seeing as much context and space as I can with each focal length. Obviously you see less context when increasing magnification, but I see till enjoy the view of the wide field.

My scope came with a similar 25 mm and 10 mm as your Scope. I chose the Explore Scientific 82 degree line of EPs due to quality, field of view and budget. I purchsed the 11mm and 6.7 mm on recommendation, and hoping to complement the EPs I already own. I wanted the 14 mm and ended up two that straddle the 14mm. I am very happy with the two I purchased. The 11mm is in my scope the most - 75% of the time. I have since tried the 14 mm and I will be purchasing it. The 14 mm will be my new go to EP. I am also interested in the 30mm too. I have not had the opportunity to try 100 degree EPs.

Given the choices i have made, if you can only purchase one good EP, then go with something in the 14-18 mm range. Over time you purchase a shorter and longer focal length EP to complete your line of EPs. Example: 30, 25, 14, 10, 6 mm. I have used the green EPs. They are great, but not in my current budget. If these are in your budget, I really like the 17mm. It would complement your EPs focal lengths and will be your most used EP.

I have a barlow and rarely use it. Everyone says get one, and I'm sure you will. There are times it helps, but I have found you need good seeing for it to be beneficial. When seeing is very good I will use and it defintely helps increase my viewing capabilities. If you have a complete line of EP focal lengths, then you probably dont need one. I use it to see how far I can push my scope.

Parracor is great, costly and should be purchased after you have other EPs and accessories mentioned by the previous posters. Coma at the edge doesn't bother me much, so I can wait to purchase the best coma corrector after I get other items. I have a long list of accessories i need to purchase before i need a Parracor, or any coma corrector. Parracor is on my l I st I f must have accessories - however it will have to wait.

There are many other factors that affect your observation before coma becomes the priority. Dew, frost, finders, filters, focuser........once you started you will discover what is important to you now and what is nice to have at the appropriate time. I want a moonlite focusr, I settled on a lesser quality and lesser cost dual speed focuser as an upgrade to my single speed focuser. I am very happy with that decision. It's easy to get caught up in the hoopla and exceed your budget.

Have fun, enjoy, spend your money wisely, observe, and clear skies.

Pages: [1] 2 3 ... 8