Tuesday, August 07, 2007

Hirsch f/6.3 SCT reducer arrived

It's on my desk this morning when I back to work, I was off duty yesterday.

It comes with a thick black paper box (typical), and a piece of lens cleaning cloth, no end caps. The lens sit inside a very well machined cell, pretty much the same as my old Celestron model, it also comes with a rubber grip, very nice.

The 41mm lens comes with deep greenish coating, very uniform and without any defect, high quality and nicely applied. On the cell, it marks "HIRSCH f/6.3 SCT Reducer/Corrector", no "made in XYZ" or any other indication.

If you asked me, I would say it's from the same factory of those well known brands. But since there is no "made in Japan" there, I'd guess it's more like a clone, a very well made clone.

I got it from ebay, the price including shipping is less than a 2nd hand one from astromart or any other place. It's more than 40% off from the new one from Celestron/Meade.

Visual testing and photographic testing pending.

1. C5 with f/6.3

I was so lazy not to test this combination. The NGF-S was attached to the C5 and thus I was lazy not to remove it and reattach it just for testing. Jupiter was there on the sky so I prefer to take images rather than testing equipments.

Do it later.

-- Finally "later" comes --

3 sets of blade measures 13.91 with reducer in PS, and 16.54 without, so the reduction factor is 13.91/16.54 = 0.84x

It's done with the reducer sandwiched between the C5 rear port and 1.25" visual back.

2. Borg 45ED II with f/6.3

Since the NGF-S was with the C5, this scope has no focuser now and it's too short to reach focus. Therefore, I've attached the reducer to the 2" visual back via a 2"->SCT adapter, and then I use a 2" SCT visual back after the reducer and to connect to the eyepiece. It could reach focus without problem, the field of view seems sharp, but the magnification is too low to tell the quality, also, terrestial targets are not suitable to really test the optical quality.

Since I was to shoot Jupiter, I didn't even measure the effective reduction factor, too. Preliminarily, I would say, with a 1/4" to 1/3" CCD, there should be no problem. However, the real question is a DSLR - for if I were to stay with small CCD, I'd rather go for a f/3 reducer instead of this one.

-- Some more test --

When the NGF-S is attached, the whole system will only reach focus when the reducer is sandwiched between the focuser and the 1.25" visual back, even the 2" visual back won't work. There's insufficient in-travel by a hair. Field of view is noticeably wider.

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