Posts Made By: Ed Blankenship

Could the SCT be a "ACF" ? If so, then the Advanced Coma Free 8 inch SCT would be my choice between the two. Tell us more about how you would mount these two scopes ?

Sorry, I meant this for the "Beginning Astronomy" forum or the "Equipment" forum, but it ended up here: My Error !

Thomas Marshall said:

Are the Meade Super Plossl's . . . same as the Meade's . . that I bought in the 1990's?? . . . So the 26mm I just ordered should match exactly with my old 26mm?? Thanks - Thomas M.

First, a few questions: (1) Does yours have JAPAN marking on it ? (2) Will the new one say CHINA on it ? IF (1) is true and (2) is also true, then no, probably not. The manufacturing sites have changed for many of the optics over the years.

Question: (3) Are you wanting an "exact match" or just "simmilar" optical characteristics like "Field-of-View" and "eye relief" sothat they can be used in a bino-viewer (Note that your eyes are most likely different, like mine are. Very few people have "EXACTLY the SAME, PERFECT EYES" so some want "EXACT DUPLICATES with consecutive serial numbers" but most people can "LIVE WITH" eyepieces made (A) in the same country (B) Same brand name, different countries (C) Same optical properties, different brand names, same basic design "ITS-A-PERSONAL-PREFERENCE, you decide.

Observation: Price points in 8-24mm Zoom eyepieces vary tremendously. I own several MADE-IN-JAPAN (REALLY NICE) VIXEN ZOOMS (List at $200 new way back then). Now on the used market they get confused with other 8-24mm zooms with Celestron, Meade, etc. markings on them. I think their fundamental design has roots in common, but some here ONLY WANT THE TELEVUE "CLICK-STOP" 8-24mm ZOOM !!!

I hope that helps some. I also hope that others can "chime in" here as well. Best Regards, Ed

Hello Jo Luijten,

I looked up your Celestron Powerseeker 127EQ and I can understand that you are having problems taking photos of the Moon. I would suggest that the EQ-1 mount is the bigger problem, vs. the Newtonian nature of the telescope itself. On a sturdier, better quality, tracking mount, the Newtonian Optical Tube Assembly might actually work better or OK, but I'll leave that for now.

I have some experience with the iOptron Cube GPS GOTO mount (which can either be an EQ mount or an ALT-AZ mount) that you asked about since I own several iOptron mounts. I've used the Cube in both EQ and in ALT-AZ and in my opinion the ALT-AZ mode is easier for beginners. My first iOptron Cube was similar to the setup you saw in your link. The other two answers you received so far are "no" and "go Read a book" I agree with both, but wanted to explain why. The iOptron cube is not a bad choice for learning about GOTO mounts (which is a steep learning curve for most beginners), but the tripod it comes with is too light weight for the purpose of holding the mass of the scope solidly enough for any type of astrophotography. I have used chains (see link below) to make my tripods less flimsy and then have moved the cube to an older, more solid wood tripod. That helped a lot. Leveling the mount IS KEY FOR AN ALT-AZ MOUNT and making an initial guess where Due South is also very important, but a magnetic compass can help here.

A real torpedo level instead of the tiny, junky bubble level is a key to success as well. If you get the ALT-AZ mount level, then the mount "knows" where the center of the earth is at (exactly straight below). Then you only need to "sync" to a single object, like the moon and correct for the offset (in azimuth only) between where south really is compared to where you told it where you thought South was at. Do this by changing the azimuth only to make the green laser (see below) point to the real object and you are "off and running" to find things near your first object. Learning on Jupiter or the Moon (or the sun) make life much simpler than starting with all those alignment stars that most beginners have trouble naming or finding. Expect to learn the star names over time. Practice when it is cloudy or still daytime. Put a wood pointer in place of the scope and get to know the iOptron Cube first, then take it outside in the daylight and use the sun and the shadows on the ground. Use the full moon, then 1st quarter moon with the scope and the green laser (See below).

A few years ago, I had looked at the predecessor to the inexpensive refractor you had a link to and instead decided to buy the Maksutov Cassegrain 90mm ("Mak" for short). A Mak is a long telescope in a short package. The key difference is the Mak is a higher "f" number than the refractor (f13 vs f5). Your current scope is 1000mm focal length and 127mm diameter which makes it an f = 1000/127 = 7.87 or about f8. If I understand you correctly, you are having trouble getting a good focus with your f8 ? The focus travel is shorter for a f5 and longer for a f10, so it is twice as easy to get and f10 scope to focus since the focus knob travels twice as far in an f10 as in an f5. I think you need a longer focus travel, not a shorter focus travel. Another thing to consider is a two speed focusser (which has course and fine adjustment knobs).

The f5 refractor is also a poor choice for your application because it is so fast (low f number) that it would have significant false color on bright objects like the moon. The Mak does a much nicer job on the moon because it is a slow system AND because it uses mainly mirrors to focus the light so that Reds, Greens and Blues all come to focus at the same point. In contrast, the low cost f5 refractor only uses two lenses that are an inexpensive attempt to get Red & Blue light to come to focus in the same place (called an Achromat) but this means that Green and other colors aren't precisely focused when Red and Blue are and there is a problem with false color "halo" effects (mainly Violet) messing up your views. Expensive refractors use either more glass (triplet, 4-lense Petzval, etc.) or use very expensive glass that makes the expensive telescopes APOCHROMATIC instead of ACHROMAT only.

I have only used my setup for visual observations, so your experience will be different if you try your camera. I use a 40mm (x30) eyepiece and a 8mm (x175) to 24mm (x50) zoom eyepiece with the Mak 1200mm, which gives me a good visual experience.

The 90mm Mak with a sun filter does a really nice job of viewing sunspots on the full disk of the sun and the transit of Venus across the face of the sun was very nice. At night, the Mak does well on the moon and bright planets like Jupiter and Saturn. Mars is harder, but with the co-operation of cool-dry-thin air of the Cascade mountains far away from the lights of the city, Mars is very satisfying every other year when it is in good position (called oposition). I junked the lousy finder on the iOptron unit and mounted a Green laser in its place. With careful mounting, I am able to see the green laser in the eyepiece and get it exactly centered in the eyepiece. This is necessary to accurately align the Cube Mount to two stars. when this is done, the GOTO works very well. One caution is that the 12 Volt DC connection can be flakey. I had to research and buy the correct connectors so that I could get a reliable power connection to the Cube.

In summary, "No" is a good short answer, but if you are willing to invest the time and spend the additional money, the iOptron (with the Mak) can become a reasonable next scope for you in my opinion. Or keep your 127, add a new focusser, look at the iOptron MiniTower to put it on and keep having fun with astronomy !!!

I hope this helps,

Ed

P.S. Check out this link: http://www.cloudynights.com/page/articles/cat/user-reviews/review-of-the-ioptron-smartstar-a-%E2%80%9Ccube%E2%80%9D-mount-r2662

P.P.S. Here's the Mak: http://www.ioptron.com/product-p/8740.htm and here's the Mak on the Mount :http://www.ioptron.com/product-p/8604b.htm

P.P.P.S. Here's the Green Laser pointer Link: http://www.telescope.com/Orion-SkyLine-Deluxe-Green-Laser-Pointer-amp-Telescope-Bracket/p/24780.uts BUT Note that the Orion Shoe is bigger than the iOptron finder shoe, so you will need to make an adapter. I know, Is this really for beginners ???

Thanks Tom for posting the two nice images of the Mercury transit from yesterday. I observed in both white light and in H-alpha over the several hours from the Goldendale Observatory here in Washington State. We had a nice time over the last 2/3 of the transit which was already in progress when the sun rose about 5:30 am PDT. I was able to look in a 6 inch f/15 refrator with a white light filter on a huge GEM, and was able to look thru my 8 inch SCT with a white light filter as well as my PST for the H-alpha view. The Obervatory also was live streaming images from two different H-alpha scopes (a 6 inch Lunt and another shorter focal length refractor) both were each equipped with a HD camera so that we could see real time H-alpha images at 30 frames per second. Your images are very representative of what we saw yesterday and will serve as a nice reminder to me.

Best Regards, Ed

I concur with your main points Thomas. I would add that the factory packaging DOES NOT GUARANTEE that the product will arrive undamaged. It only strikes a balance between protecting the product WELL ENOUGH to produce an ACCEPTABLY LOW FAILURE RATE of the many, many products that particular factory produces and sends into the shipping environments. Manufactures BALANCE less PACKAGE cost against costs of a damaged product making it to the customer and affecting the costs associated with replacing a damaged product. Also, if the carrier can be held responsible (or not) to eat the cost of a damaged product. FOR US SHIPPING ONE OR TWO PRODUCTS, we can't cut the packaging costs as slim or we risk eating the loss because the shipper doesn't view us as "PROFESSIONAL" product packers like they do Meade or Celestron or Televue, . . . for the large manufacturer, is is a game of STATISTICS and EXPERIENCE, but for us, OVERPACKING is often better than a broken product !!!

Have you looked thru it at an object that is relatively close (like your keys on a table 6 inches to a foot away). If it is a 4x Barlow, the keys will look significantly smaller and further away. Can you then get an image of the keys (or a ruler) with and without the RINI 4x interposed in the path between the camera and the keys/ruler. Then take a photos of the threaded end with a ruler in the photo and post these photos here or on Cloudy Nights site.

Hey Optics gurus, any further ideas on how to make this ID of a 4x Barlow more certain ?

Very beautiful music - Thanks for sharing - Very moving indeed !!!

Hi Chris,

It would help us to help you if we knew a couple more details about your Celestron Eyepieces: What focal length(s) of eyepieces do you have that you might want to use with a Barlow ?

For example: if you have a 24mm eyepiece, a 2x barlow will make it seem like a 12 mm eyepiece. And it follows that a 32mm eyepiece would work like a 16mm eyepiece with the same 2x Barlow.

Ed

Hi again Chris,

It would also help us to help you if we knew either the "f ratio" of your 6 inch Newtonian or the "focal length" of the scope. For example: if your scope is an f5 then the focal length is 6" x 5 = 30" or in mm that becomes 152mm x 5 = 760mm, so a barlow would make that 760mm x 2 = 1520mm and then you could compute the "power" of the combination of the scope and eyepiece combination (and perhaps a barlow too).

Ed