Posts Made By: Randall P Rourke

Can anyone suggest a supplier of parts for a 6 to 8 inch Newtonian project I am considering. I would like to build it in an aluminum tube and use an EQ mount. Also any tips or resources I could investigate would also be appreciated.
Is F5 too short of a focal length? Are F5 mirrors available? I am basically trying to find out what it would cost to build a somewhat premuim scope and am also wondering what the advantages over an import Newtonian are.
Also how would such a scope compare to a Mak Cassegrain?


Thanks
Randy

Hello

I am wondering if the diagonal on an Intes Micro 603 can be rotated for optimal ergonomics?

Thank You
Randy

Hello All

I have been ready lots of posts, most recently another excellent one by Mark R. and I am wondering about how focal ratio (FR) relates to deep sky performance. I undestand the effects of the central obstruction as it relates to the MCT vs MN. and also understand how the FR relates to field of view.

However what I am wondering is does a shorter FR scope perform better on deep sky because it "sees the light" faster or better than a longer FR or is it mainly because a wider field of view issue.

Thanks
Randy

Hello

I am looking into a Newtonian project, and am wondering about mirror cells. The scope will be 8 inch in an aluminum tube. I have seen Parks, and University Optics. Is one better than the other. Are there some better than these. I would like to got high end here.

Also any sources for curved spider vanes, or is this a do it your self proposition.


Thanks
Randy

Hello

Does anyone have any experience with the refrenced EP scope combination. I am wondering if getting the EP to focus is an issue. Also your performance impressions. I am looking at the 503 or 603 and FOV with this EP is barely acceptable for my needs with the EP, any less FOV and I am going to have to re-think the scope choice.

Thank You
Randy

Hello

I am wondering how the performance of a premium Newtonian such as a scope Royce or Harry mirror, stacks up against a similar aperture Intes Micro or Intes Maksutov Newtonian, particularly an F6 Newtonian? Is coma significant at F6 in a hand figured mirror?

Any thoughts or experiences?

thanks
Randy

I am no expert as you can tell by my own post. But Mark's comment about string musical instruments got me to think that if you wanted to try this out, You could use a guitar string attached to a peg end and a guitar tuner on the other end, to tension the string. A locking tuner would be a nice choice. This would allow you to tension the strings pretty tightly as well as experiment with different gauges and tensions. Use two pegs and two tuners, to make a cross hair pattern and then tap for holes into the back of a secondary holder, position the holder and use a round backing plate and four screws to hold it in place. Perhaps a groove in the backing plate would be necessary since the strings would overlap.
Anyway it is just a thought. Plus if it gets cloudy you could always play a little foggy mountain breakdown.

Hi Eric

You may wish to contact Bill Burgess at Burgess Optical. I was talking to him the other day and he mentioned having these for $2,995.00 shipped.

Regards
Randy

Hi Tony

I have the Stellarvue AT1010 and the ETX90 (And a 8 SCT). At higher powers the ETX90 beats the SV by a huge marign. Certainly not a toy. Todd Gross compared the ETX to a TV85. And while he concluded the TV85 beat out the ETX, he was also impressed with the ETX optics enough to do a comparison. The mount is not going to win any awards, but given the the cost the value is considerable. I expected the ETX and AT1010 performance to be closer given the central obstruction in the Mak, yet the C.A. in a fast achromat impacts high power/planetary performance more than I expected.

The AT1010 on the other hand is better at low power wide field views, something the ETX90 can not do. (The ETX gets about 1.25 deg FOV). It is also costs three to four times as much money, by the time you buy a diagonal and EP. A fast achromat will show considerable false color, maybe less than an less expensive F5 scope, but it is there. For some it is objectionably for others it is not. This is not to knock the SV. An achromat is an achromat and a fast achromat is going to have false color, even an expensive one. Lastly it is not nearly as portable as the ETX90.
I thought I could mount it on the 8 SCT, but find it too large for that purpose. It is a big scope for 78mm aperture.

In summary I would assess how much portability, wide field and cost matter. If the ETX90 could get the wide fields it would be the clear choice, especially given the sales prices. The AT1010 is also on sale for $399.00, but you will need an EP and a diagonal and a mount/tripod.

Something to consider with the ETX, is the ability to remove it from the mount and use it with a small inexpensive GEM mount.

I do love wide fields, which is why I bought the AT1010, Yet I find it overpriced for what it is. The ETX RA, given the sales prices is a though act to beat, yet the wide fields of the AT1010 are nice...though choices..good luck.

Thanks
Randy

Hi Larry

From what I understand and suitable mount is also in the works. The Burgess GEM1 will work fine for the 102 F6. However the 127 F8 is a larger scope and pushing the limimts of the mount. Bill is telling me that the heavier mount will be available in May, it will be a GEM style BTW.

If the wait is a problem, a Meade LXD55 GEM should work. It may not be up to the task for the AR6 and 10SN scopes, but do seem to work for the 8 SCT, 8SN and AR5. Although with the added hieght of the refractor requires a taller more stable tripod would be desireable.

In talking with Bill Burgess, the new mount will have a suitable tripod as well, which could make it worth the wait.

Randy