Posts Made By: Steven Jindra

I have been out of imaging since Hurricane Ike last year. The house is now back in good order and I just ordered (on Amart) a 2" 13mn Ha filter and the imaging juices are starting to flow again. With the 2" Ha filter, I want to try out a few wide field imaging trains with the 2" Ha filter before the focal reducer, and would appreciate any comments on anticipated benefits or problems.

Wide Field
FS-60, 2" Ha filter, .63 FR (SCT type), SXV-H9 imager.
Approx result - F3.8, 230mm focal length.

Widest Wide Field
FS-60, 2" Ha filter, .33 FR (SCT type), SXV-H9 imager.
Approx result - F2, 120mm focal length. I am anticipating probable vignetting.

Thanks
Steven Jindra

This week, I'm to receive that ugly Mewlon-180 that pops up on Astromart every year or so. The original owner drilled holes on each side to install a small cooling fan and allow for air flow (see picture) for quicker cool down. I remember in one of the ads past, the original owner said he cut the holes back before he fully appreciated the ascetics and beauty of a Tak OTA and would not have done it if he had it to do over again.

My intent was to install some heavy white reflector tape to cover the holes, but am also considering going ahead and installing a small computer type fan. I live in the Houston area, so the temperature drops are not as dramatic as some places. The OTA will usually be stored in an outdoor building (no AC or heat) and set out for viewing. Any opinions on installing the fan (or not) or how best to minimize the cosmetic damage?

By the way, I purchased a Nexstar 8SE alt-az mount for this OTA with the intent of it being an easy to set-up combination for visual use only.

I did have one bad experience with colimation one of these, so I'm pressing on with the intent that I will get the knack of colimating this OTA, as I have been spoiled by refractors for the last several years.

Thanks for your thoughts.
Steven Jindra

I just ordered a SV102APO with FT focuser from a fellow Astromarter to use as my quick look scope on a TV upswing mount with sturdy tripod. It's an F8.somthing doublet that is no longer made. Some nice expressions amoung the SV group. Any experiences or comments about this scope while I am waiting for delivery?
Thanks
Steven Jindra

With the CCD chips getting larger and larger, and imagers reaching more and more for perfection, I'm looking for additional insight into the world of field flatteners and focal reducers. I personally have a Takahashi 2.7" FF/FR (FC-100 FR), a Takahashi 2" (FS-60/78/90 version), a Meade SCT .33 and a .63. In times past the FC-100 FF/FR was recommended for the Tak triplets. Now the FF/FR for the triplets is also recommended for the older FS doublets. Takahashi is adamant about the correct rear metal distance to the CCD. The Meade SCT .33 FR says to vary the distance to vary the reduction. Most FF/FRs suppliers recommend a certain focal length and some a certain focal ratio. Some specify a certain metal back distance to the CCD, some do not.

1.How proprietary are FF/FR and FFs?
2.How much benefit do you loose when crossing over to differing OTAs (triplets, doublets, differing focal lengths, ratios)?
3.How critical is the metal back focus on most FF/FR and FFs? How bad is 3-4mm off?
4.What about using an SCT FF/FR with a refractor? Or Vica-versa?
5.Is there a rule of thumb for the size flat field for a 2”, a 2.7”, or a 4” FF/FR or FF?
6.Any good reviews, articles, or books on this subject?
7.Any other related subjects?
8.How about rating the FF/FR and FFs you use with your OTA and CCD imager combinations?
9. How about from a designer/manufacture's standpoint (the ones who provide us such fine tools)?

Pros (Roland, Markus, etc.)and amateurs, please pitch in your comments or experience.

Thanks
Steven Jindra

Which non reducing field flatters would match well for imaging with an SV115T35 115mm F7 APO triplet
with the 3" Feather Touch threaded focuser and a Starshoot Pro II imager (25.1mm x 17.64mm - 31mm diagonal). I have the adaptor to Takahashi 2.7" accessaries theads already.
Thanks
Steven Jindra

I recently purchased a Canon DSLR (7D) and macro lens (100mm F2.8 L IS) and am enjoying taking a few handheld macro shots, especially of backyard bugs. I am thinking of purchasing a flash or LED ring light to compliment this lens. I appreciate any recommendations from ones more experienced? Pros and cons of differnt flash units or the constant LED rings.
Thanks
Steven Jindra

I am looking to mount my FS-128 on a Gibraltar Mount for quick and easy astro and terrestrial setup. Would anyone provide me the measurement from the center alt axis to the top of the bottom plate and the inside saddle dimension from one side to the other for the Gibraltar and for the Gibraltar 5 saddles?

I expect to install a plate (probably to the bottom of the saddle) extending to the forward and the rear, to install the two OTA mounting rings to.

Anyone using this combination or similar? Okay? Problems?

Thanks
Steven JIndra

Anyone using this combination or similar? Okay? Problems?

I am looking to mount my FS-128 on a Gibraltar Mount for quick and easy astro and terrestrial setup. Would anyone provide me the measurement from the center alt axis to the top of the bottom plate and the inside saddle dimension from one side to the other for the Gibraltar and for the Gibraltar 5 saddles?

I expect to install a plate (probably to the bottom of the saddle) extending to the forward and the rear, to install the two OTA mounting rings to.

Thanks
Steven JIndra

Anyone using this combination or similar? Okay? Problems?

I am looking to mount my FS-128 on a Gibraltar Mount for quick and easy astro and terrestrial setup. Would anyone provide me the measurement from the center alt axis to the top of the bottom plate and the inside saddle dimension from one side to the other for the Gibraltar and for the Gibraltar 5 saddles?

I expect to install a plate (probably to the bottom of the saddle) extending to the forward and the rear, to install the two OTA mounting rings to.

Thanks
Steven JIndra

I have a tough decision to make. I have two very nice APO refractors, an FS-128 and an SV-115 APO. Both are excellent, but I find I no longer have the stamina to regularly stay up late night astroimaging and/or viewing these days; by 9pm I'm usually out like a light. So one needs to go.

Recently, I've become interested more in nature photography with a recently acquired Canon DSLR. So the scope I keep will be used for long distance nature photography and for those nights when I'm up to viewing the planets (I'm primarilly a planetary viewer) and other more distant objects. .

The FS-128 gives me a full 5" APO as a fluorite doublet in a large, but relatively light package. The SV-115 APO is an ED triplet, is a little more color free, is smaller, but a little heavier. The SV-115 will work on a TV Gibraltar mount. I've been considering the Gibraltar 5 for the FS-128, but don't have one to check this combo.

I'm going to compare both for terrestrial photography and if one shows a distinct advantage, that will sway my decision.

I know there will be sellers regret either way, but I've taken cash from our bank account for DSLR lenses, so I've got to balance the books.

Appreciate any thoughts.