Rodd

I have to pick a lane and keep at it--no changing lanes after a purchase like this! When not overloaded I get rms errors between 0.05 and 0.25 arcsec (usually below .2 more than this and I tinker). How else to know but by weight? All I can do is calculate the reported weights of the various items and see if it is below the stated capacity of the mount. I recalculated the FSQ with a 3 pound camera and np101is with a 6 pound camera--I think its too much weight for the Mach 1-certainly right at the limit. I would need to get a second np101is (5 pounds lighter). But getting a second np101is is the least appealing purchase in front of me. Rodd

Not really--you would either do 1 or 2--but which

Free is certainly not a description I would use in this pursuit! But now you have me thinking. As a person who knows nothing about running a duel system, it seems to me that running 2 independent systems is simpler. I just do what I do now on 2 units. Since I need to buy a major piece no matter what path I choose, I have more options. Which of these makes more sense: 1) Purchase new mount (AP1100-capacity 110 pounds) and use it for a duel setup of TOA 130 at F5.4 (reduced) FL of 700mm, and the Televue np101is, FL 5.4 (unreduced) FL of 540mm. This option also allows me to use 2 independent systems if I just can't get the duel setup working. Also, it sets me up for adding a bigger OTA at some point. If I calculate it right I would be shooting at an effective focal ratio of 2.7. 2) Purchase second np101is or FSQ and try to run duel setup on my current mount. Assume the weight works (it will be close, but I think its dooable). This option allows for the use of the FSQ singly with .6x reducer fopr F3 3) Buy the OS RH200 and use it by itself on my current mount. Rodd

Enter the ASI 1600. the camera is begging to be used it seems. But shorter total exposure time is not what it represents, which is what I want. I am not really interested in many short exposures vs fewer longer exposures with similar total integration time. Due to the bit depth, you have to stack 200-300 (per filter) to compensate. Not familiar with other cameras. Rodd

I was more referring to the long exposure vs many short exposure issue--maybe the 2 issues (scope type and exposure length should not be mixed). With a given scope, no amount of 20 sec exposures can reveal the faint details reachable with a 1 hour exposure--or lets say with the maximum exposure for a given location with respect to sky fog). True?

That sharpens the focus! If I am going the dual rig route--why not use the np101is I already have and get.....yet another np101is (talk about redundancy). I suppose the 2 scopes don't have to be identical. An FSQ at F5 would work with the TV at F5.4 I suppose. But.....I think that the word "Risk" must be used with respect to mounting concerns, dual computer use, dual camera use, etc. And here is a statement some one said regarding the np101is (or any fast refractor) and the OS RH200 ....."there are faint details descernable with the OS scope that will NEVER be reachable with the np101is regardless of the length of the exposures". This is similar to the many short exposures vs 1 long exposure. There are photons captured at 30 min that give detail that just can't be had with 60 sec exposures, regardless of the number of 60 sec exposures--even a million. They are so faint that it takes 30 min for the signal to reach a level of detection. So my question is if you use 20 F10 scopes and I use 2 F5 scopes and we both take 1 min exposures, would the images be similar? The dual rig sounds great--I do have mounting concerns and weight concerns--not to mention logistics concerns. But maybe I will think about it. Rodd

The option I don't have is SPEED--Even with the TVnp101is at F4.3 I shoot 20 hour images. That equates to weeks of time due to inclement weather/Moon. Focal reducers are great at widening the FOV--but time reduction is not as clear cut (the myth). That is the biggest reason I do not get the FSQ--it will be reduced to F3. I don't see much difference in time between the TV at F5.4 and F4.3. I am not confident that the FSQ will be as fast as the OS because of this. But thank you for your input--I am thinking about things from a slightly different angle now, which is gppd Rodd

Regarding the Rowe--I have never been a fan of the front mounted camera--The cable issues, diff spikes, plus it weighs a bit much for my mount (I can image with 45 and the OTA alone it weighs 36. I would definitely go for the RASA over hyperstar though- Regarding the aperture issue, here are my concerns 1) The OS RH 200 is not a full 8 inches due to the 30% obstruction, so it actually is slower than F3, while the FSQ 106 is a bit more than 4" and it would shoot at F3 2) The OS scope carries tilt and collimation frustration, which equates to loss of imaging time. Maybe its not as bad as "they" say--but it certainly is worse than the FSQ 3) There is also some evidence that there can be star bloating in the OS RH 200 but I do not know the details. 4) The FSQ has 2 ED lenses, is fully corrected, has a monster imaging circle, and is proven. I like the TOA 130 stock focuser (never tough it manually or with eyepiece so I don't know what all the fuss is about)-so I won't have a problem with the focuser of the FSQ--while I may need to concern myself with the focuser of the OS RH 200--not sure. The FSQ 106 is one of the most popular imaging scopes out there. It is tauted as being among the best refracting astrographs available (possible only exceeded by the FSQ 130--Hmmmm---maybe that would be better). Yet you would not suspect this to be the case from the comments on this thread. From this discussion, one could conclude that both scopes are wild cards, and aperture is the deciding factor. Maybe it is...I don't know. But then why are not more people using them? I don't know. I am n ot saying you are wrong in "aperture IS the deciding factor". I shoot with 11" at F7 and quite frankly I don't see any difference between the C11Edge at F7 and the TOA 130 at F7.7 as far as speed goes. Maybe a little, hard to say--and teh difference in aperture there is 7 inches.

The OS RH200 does not have diff spikes I do not believe. The FLI cameras are big bucks (I would need a big sensor with small pixels--quite rare).

How does front or back illumination effect speed? The highest QE I know of is %76-80, can't recall the camera--it may very well be the ASI 1600--or one of the HAD chips. That is what makes this particular choice very difficult--the cost is about the same for me (due to what I need to get to set it up the way I want). Also--I have to be able to use my current mount (Mach 1)--so I am limited to a fast Newt of about 8" (maybe 10 for some brands). But they are F4. Plus I don't like diff spikes and avoiding collimation issues would be easier with a higher end scope. Maybe an ASA. Anyway--there is paper and theory, and then there is reality-not always the same. For example binning 2x2 is suppose to be 4x faster than 1x1. It is not. Not even close. so some personal experience would be great--even anecdotal. I know Paddy uses an OS RH 200. Rodd

Yes...and a plus would be that even though a mosaic is the plan, each of the panels would make a pretty good image in itself. However, bear in mind that even if I get the FSQ 106 and shoot at F3 with either my STT-8300 or the ASI 1600mmcool--it isn't really a widefield setup. Not like a KAF 11000, 16803, or ATIK 16200, to name a few. That is one reason this decision is so difficult, because its not only what I will be able to do now, but what is possible with future additions/modifications without redundancy (or limiting redundancy) The real question is--which scope would more likely allow me to complete an image in 1 night--whatever type of image it may be--whether a widefiled image, or a narrow filed image. I will take the image for what it is--so no myth involved. I can use either camera on either scope. the primary variable that I want to target is speed. What ever I can get in a short amount of time. If I set up a true widefiled kit, I will want to set that up so as not to be constrained by anything but image quality (which will include speed I am sure, but it won't necessarily be the driving factor). Unfortunately cost is always a factor. At present I see 3 choices. Buy the ASIO 1600 and use it with the Telvue at F4.2 (pixel scale of 1.81), Or get either the FSQ or OS RH200 and use them with the STT-8300. I can't buy them all! Rodd

Here is another--far cheaper option. Use the Televue np101is at F4.2 (reduced) and get the ZWO ASI 1600mmcool camera. Will the sensitivity of the ASI 1600 coupled with the F4.2 speed of the Televue, be faster than my current STT-8300 and the Televue. If the answer is yes, this may be a good option. Ther np101is is a fine scope and I have always wanted an ASI 1600mmcool. Rodd

If that is the case-- I do not mind a large FOV for Widefield (I already have mid and long focal lengths covered)--especially if I get the ASI 1600mmcool with its little pixels--the scale would be 2.39 arcex per pixel which is pretty good for wide field. But, here is the real question--I know they are both F3, but for a certain focal length, aperture will effect speed. An 8" scope with a 500mm FL at F3 will be faster than a 4" scope with a 500mmFL at F3. But the focal lengths are not the same here. As I am out for speed, I am trying to determine which scope would be faster. And--would there be a significant difference. In other words--would the extra 4-5 inches of aperture make up for the 2x focal length as far as speed. And its not single sub speed I am most concerned with--its whole image speed. I want to complete an image in 4-5 hours total exposure time. The other interesting point is the 106 is many, many times more commonly used than the OS scope. I am wondering why. For me,needing ASI1600mmcool camera, OAG, guide scope and USB port if I get teh 106, the cost of the 2 systems would be comparable (within $500), so teh $ is removed from teh equation. My choices for speed were 1) Epsilon 180 2) FSQ 106 at F3 3) OS RH 200 at F3 (not interested in Hyperstar or RASA) Rodd

Its called a discussion, gentleman--that's what forums are for. Rodd

With respect to his choice, or his ire? Rodd