10" F/11 R30 Report

[mikey cee]

My oh my is all I can say! Hot damn man! The minute I viewed Altair I knew full well what this lens was capable of so no further use of the lens was needed. ;D Just a little wry humor to get your goats. Anyway this larger aperture shorter FL lens is outdoing the Brandt 8" F/13.3 on CA. There are flares and spikes at the bottom of all stars and Jovian moons. This because it hasn't been collimated yet. With a laser we also still have to adjust the 10"x32" tube so that it is perfectly on the optical axis. But even so the lens is showing as much detail and more between seeing turbulances. What really took me by surprise was the ease at which I could look straight at the star close to M57. With the Brandt I had to use averted vision in this urban sky. Ales you and Zdenek will have a tough time besting this. Maybe you boys just got lucky....but what do I care now. ;D ;D I was able to get a 10" F/14.3 into my existing space.....that's what I was after. I even got the tube length correct so my binoviewers had an inch of in travel left with 25mm plossls and no barlow for star filled low power dark contrast sweeping in urban Omaha skies. That alone is worth the price of admission. Therefore to say that I'm a satisfied customer is the understatement of the day. Thanks to Mike H. for double checking those "other" two. ;D Mike

[borispider]

Sounds awesome Mike.

[Watcher3]

And with that, the chorus of happy Istar customers becomes a deafening ROAR!

Congratulations Mikey, and thank you Istar, for making big refractors cool again.

Joe

[astrosean]

Fantastic! Congratulations... I've been waiting to hear how it turned out!

Sean

[Ales - iStar Optical]

Hello Mike, would you be so kind and write up some kind of more complex first light report for us at Istar Optical. I would like to have our graphic guy Petr to post your complete review incl. some photos on our web site. Your help will be greatly appreciated, thank you so much in advance,
Ales
ISTAR Optical, owner

[mikey cee]

Hi Ales....Gladly will do. I am waiting for my dewshield first. I just completed my collimation yesterday. Now the darn weather has turned so don't know how soon I'll be able to start star testing. So I can't say how soon but I'm just as anxious too. Mike

[mikey cee]

Well the scope redo is just about 98% finished. Over the next week or so I hope to have 2" conversions on both scopes. John has to make me some adapters to fit my 2.7" drawtubes. I'm shopping now for some used 2" diagonals. The 6" scope will need a second adapter to fit the wide field Jaegers military erfle. Also by sliding the 6" further back even with the main scope's focuser I'll be able to shift even more weight to the rear. This will easily allow me to rid the main scope of those 3 little 1-1/2 pound weights which are near the Dec knobs. With the Moon coming up later and later I hopefully will be able to give the new lens a thorough testing. Of course that'll depend on the seeing conditions. I feel from my first few observations that the new 10" lens has slightly better CA control over the 8" Brandt. Sometimes it seems better, then at other times when you just aren't that positive. Let me remind you that that Brandt lens will be hard to top because it has a near perfect airy disc pattern both inside and outside. I would never bet on being able to top it on double stars. If the 10" holds it's own in this regarde I'll be tinkled to death. But I know this much. If that 10" F/11 lens was a simple achromat corrected for the usual C and F lines it would definitely display well more color than the Brandt 8" F/13.3. But the R30 recipe has allowed it to do no worse and in fact better on the craters of the Moon and Jupiter's limb at 350x. The CA appears to be a more bluish lavender than the bluish purple shown by the Brandt. So on that note alone I'm doing cartwheels....in my head of course. ;D The moons of Jupiter when seeing permits are super clean little discs. Obviously with more aperture the planet looks whiter and the details are much easier to see. The seeing hasn't cooperated much to let me use higher powers. Here's a pic that John took of me looking into a glaring sun aftwer lunch today. Mike

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[mikey cee]

Another pic from the east side. You can barely make out my service hatch behind the lens. Here ahead of the Dec knobs you can easier see those little tube weights that will be replaced. Mike

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[Watcher3]

I thought with the Step down, it would look very utilitarian. It doesn't. I really like the aesthetics! Gorgeous looking scope.

[mikey cee]

Well I'm still evaluating the lens. Some nights cooperate others don't. It'll just take a little time bear with me. Two nights ago I did some double stars. Epsilon Lyrae, Delta Cygnae and 72 Pegasi. The lens wasn't quite "cooled" as some "bushiness" still flared from the stars especially a half our earlier when I looked at the double-double. Next was Delta not as "bushy" and that secondary was so tack sharp I could hardly see it. ;D Lastly came 72 Pegasi. A pair of yellow 6th magnitude stars seperated by .53 arc sec. The lens was close to cooled now but couldn't be sure due to a slight wind that kept the scope bouncing at 361x. All I could see was a "peanut" with glimpses of darkness between them that jumped in and out with the scope's movement. I need a second opinion here.....is that any indication of a super well figured lens or not?? ;D ;D Mike

[Mike]

Mikey, I have recently developed an interest in doubles. I've been imaging them when possible. Zeta Aquarii is a double of equal magnitude and a separation of 2.2". I thought that was close but .53"... Wow that is really close. I will try it later this week and get an image if possible. Any others you really like?
Mike

[mikey cee]

Yeah I like Pi Aquilae but it is getting low. A few others are Iota and Eta Cassiopia and Gamma Andromeda. Mike

[mikey cee]

Just came in to warm up a bit. It's near mid 30's outside. Calm and transparent well at least for being in the southern Omaha metro area. Finished looking at 72 Pegasi again. I've got to remind myself when these temps fall like a rock that lens needs time to adjust...a lot more so than the 8" did. Still a "peanut" with a bunch of stuff floating around it like a faint colored brushiness that disappears after the lens stabilizes. Went to the zenith for Andromeda. At 108x the core was ablaze but couldn't detect the dark lanes. I really wasn't looking for them but they didn't jump out at me either. Then I pushed the core out of view and a little ways out there was M32 fairly brite I must say. Then off in the opposite direction to look for NGC205(M110). I found it with no difficulty. I never could find it in the 8" even tho' I had the proper starfield. Wow what a find. Next week I'll be ready for M1. Mike

[Mike]

Yeah now you got my motor running. I'm wondering how big I can go and still be reasonably portable. The dreaded aperture fever. I'm not ready for a permanent mount yet. With Istar growing and changing I'm not sure where I will be in the next few years. If Ales has his way we'll be in Arizona in a couple years. Guess I'll have to try to stick it out with a 6". I'm really contemplating an 8" APO (got to keep it short for now). Has to fit on my CGE.

Mike

[Mike]

I used an 11" Celeston for several years and DSO were really bright in that. An ethos 21 and that C11 looking at M42 was a site to behold. HUGE amounts of detail. However, not even close to the contrast of a "BIG" refractor like you are using. 10" has got to bring in some serious light. Have you stayed out late enough to see M42 overhead?