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Thinking about jumping into EAA

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#1 SamplingNature

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Posted 14 August 2019 - 08:09 PM

Hello, everybody!

My fiance and I have recently decided to get into astronomy. I have a little bit of experience with a telescope, dating back about 10 years (with a Sam's Club Meade "Bird Jones" Newtonian on a Go-To mount. DS-something). She is just now getting her feet wet. We've been getting out when we can, weather and work schedule permitting, with binoculars for the past few weeks.

After seeing the Moon, Saturn and Jupiter up close, she has decided that she wants a telescope NOW! To hit that mark and keep her momentum going, I'm planning on picking up a Meade ETX-80 in the coming weeks.

I, however, am looking further down the road. I think that we'll be very happy in the longer-term with a combination of visual and electronically-assisted astronomy. In addition I think it will be a great experience for our son (he's five, highly-functioning autistic and a genius).

I'm currently working on a savings budget to purchase an adequate kit by next year. I think that, all other things considered, we can shoot for about $3,500.

Here's what I'm considering so far:

Celestron Nexstar 6se with the addition of the Celestron electronic focuser and Telrad finder.

Dew shield, dew controller and heater straps for the corrector plate, eyepiece and Telrad.

For the camera, I'm somewhere between the ZWO ASI224 and Revolution R2 (I like that the R2 comes with a screen, potentially eliminating the need for a separate laptop).

For visual, I'd like to get nice eyepieces, so I'm considering the Baader 8-24 zoom with the dedicated barlow system and a quality 32mm. I'd also add a decent illuminated reticle eyepiece for more precise alignment.

I'd likely be powering the entire rig with with a Die Hard jump box. The model I've been looking at has two cigarette lighter ports, two USB ports and at least one 120 outlet.

Bu the time I add a Pelican case for the OTA and mount, a similar, smaller case for the eyepieces and other small accessories, a cheap laptop and assorted cables, I think I'll be right at my budget.

All that said, I have a few questions. First, am I missing anything necessary for a successful EAA session?

As for the camera, which of the two mentioned would be best for live observation?

Finally, if I go with the ZWO, is a cheap laptop ($150-300) going to be adequate for use with the camera and to guide the scope, assuming I do a clean install of the OS and use minimal software (the computer woul be dedicated to the purpose)?

Thank you for your time!

#2 OleCuss

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Posted 15 August 2019 - 05:03 AM

Whether all this will work OK really depends on what you are trying to do.

 

There is nothing at all wrong with the NexStar 6SE but you have to realize that a long focal length telescope (like the 6SE) tends to be more sensitive to tracking errors (and its mount is not great) and to atmospheric turbulence.  You also end up with a narrow FOV which makes finding and tracking your target a bit more difficult.

 

Something like the Astronomics 6" imaging Newtonian would have a much shorter focal length and be easier to image with.  Some complain about difficulty getting good collimation but others find it fairly easy.  You'd have to get the mount separately but you might get a Celestron Advanced VX at a reasonable price - perhaps used.

 

An OTA like the Omni XLT 150 has a bit longer focal length than I like for easy imaging but is reportedly a pretty good performer for imaging.  You'd probably find the collimation a little easier.  It would likely be more enjoyable for visual use.  I'm not a huge fan of its mount but it can be sort of adequate. 

 

The cameras you are looking at have small sensors which will tend to further reduce your FOV.

 

The IMX224 is highly respected but, again, will give you the narrow FOV.

 

The R2 is beloved by some but I've never understood that (might be my failing).  It is low resolution in just about every way and makes things more complex with worse dynamic range.

 

If you go un-cooled the IMX224 is really easy/simple to use in that you run one USB cable to the computer and you are set.

 

If you grab the R2 you'll have more cabling and power demands.  If you use their screen it means you are not using a computer (which can be nice) but it is a low-resolution screen which may not even show all the pixels of your sensor (can't tell from their ads).  Use with their screen also means you aren't getting the SNR advantage of stacking in software so ultimately you just cannot get the quality most of us want.

 

The camera and software are really very important to what most of us do.  Think carefully about how to match them to the rest of your equipment and your goals.

 

Visual use (with eyepieces) is not the focus of this sub-forum but I'll give you my perception of what you are looking at.

 

I think most of us end up not using the Barlows very much.  I'm not even sure I can tell you why.  I've got 'em but they haven't been used in years.

 

The Baader zoom is a good eyepiece but has a narrow FOV.  I like mine but because of the narrow FOV for years it has been used for nothing other than public outreach.  For public outreach I've discovered a wide FOV is not good because the inexperienced get lost whereas the narrow FOV means they can only see what the OTA is directly aimed at.  Awesome to get good optics and varying focal lengths and I've gone several nights using nothing but that Baader zoom but eventually I think most of us transition to using about three good quality eyepieces and just maybe occasionally dip into something else if we are doing something unusual and we have the extras for that.

 

Pellican cases big enough for a 6SE are too expensive for most of us.  We tend to make boxes, use drummer's cases, or just a good storage boxes with blankets and such to cushion.  For some smaller stuff a lot of us are now using the Apache cases from Harbor Freight which are much cheaper than are the Pelican cases.

 

Edit:

I should point out that you can get the Night Owl reducer/corrector from Starizona and reduce the effective focal length of the 6SE to a much more manageable 600mm.  With that addition the focal length would be much easier to deal with, but your camera will be sticking out much further and may hit the mount if you aim anywhere near the zenith.  There are methods for moving the OTA further forward which might resolve this if the problem occurs (not sure with that OTA/mount/camera/reducer combination).


Edited by OleCuss, 15 August 2019 - 05:43 AM.

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#3 tmaestro

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Posted 15 August 2019 - 09:40 AM

For visual, I think the Baader Hyperion Zoom is an excellent choice for a 6" SCT.  The BHZ's sweet spot is mid-to-high magnification, which is right where the 1500mm focal length puts it.  8mm gives you 187x, which is reasonable planetary magnification for average skies and 150mm of average-quality aperture.  A barlow for the special nights, maybe.  The additional 32mm eyepiece is a good idea, as the BHZ's fov narrows quickly above 20mm and is not going to really replace longer focal length eyepieces.  

 

With that scope, you could go as low as the ES68 40mm and still have a 4mm exit pupil, which is totally usable for light polluted back yard observing.

 

Screen Shot 2019-08-15 at 9.28.15 AM.png

 

...

 

But off-topic visual observing musings aside, if I had $3500 and was starting over, I wonder what the veterans of this forum think of the Comet Hunter.  It has a wide flat field at f/4.8 and takes magnification well.  For visual, The Hyperion Zoom Barlow at 2.25x puts is focal length in the BHZ's sweet spot.  For imaging, it's at f/4.8 and doesn't need a coma corrector or field flattener or reducer or anything.  It'll need an EQ-6 or so, I'd imagine.


Edited by tmaestro, 15 August 2019 - 09:41 AM.


#4 OleCuss

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Posted 15 August 2019 - 09:47 AM

I do OAP with the Comet Hunter and it actually works well on my AVX mount.  It's a very good OTA IMHO, but the focal length is just a little longer than is ideal for easy imaging.

 

I'd not be doing long exposures with my Comet Hunter on the AVX - I doubt I could reliably get 90 seconds of good exposure with that combo.


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#5 GaryShaw

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Posted 15 August 2019 - 11:18 AM

I do OAP with the Comet Hunter and it actually works well on my AVX mount.  It's a very good OTA IMHO, but the focal length is just a little longer than is ideal for easy imaging.

 

I'd not be doing long exposures with my Comet Hunter on the AVX - I doubt I could reliably get 90 seconds of good exposure with that combo.

 

Hi

I started EAA, OAP as OleCuss would say, about 9 months ago with the R2 Imager. I would reinforce what OleCuss says about moving to a modern digital camera instead. I found the tangle of cables and poor resolution of the R2 quite disappointing and complex to use if you wanted to use it with a laptop and frame grabber to allow you to stack images. I also agree that a simple, larger aperture, smaller focal length scope might be a better way to go. Others mention the Comet Hunter. I started with my 1986 Celestron Comet Catcher which is a 5.5” Schmidt newtonian telescope. The Schmidt in the name just means it has a front corrector plate that reduces the ‘coma’ in the views. It has been very simple to use on my iOptron Alt Azimuth Mount and the combination easily handles exposures up to 8 seconds which is way more than needed for EAA when using Sharpcap and stacking images. I typically use 2-3 second exposures which easily gets me faint galaxies and nebulae in my light polluted skies. Leaning to use Sharpcap will be important if you’re planning to observe with a camera.

 

I also wonder if your son might gain/learn more from the experience by going the route of a modern CMOS based imaging camera and laptop image stacking with Sharpcap, the application that most folks in this forum seem to use. He’s young, but if you introduce the technology very gradually, in combination with eyepiece observation and combine it with teaching him in stages about the universe and what objects are out there, he’ll likely get the bigger picture of both the science of astronomy and the technologies folks use to observe and study it. Sharpcap will also give you all a ride for your money in learning about how a CMOS camera turns photons into beautiful onscreen images - as you learn to manipulate the camera settings and adjust the imaging histograms to optimize the view of deep space or solar system objects.

 

Anyway, I’ve run on enough so I’d just end by encouraging you to read more of the sub-topic postings in this EAA sub-forum - especially those initiated by others also starting out in EAA. These have been a terrific resource to me and you’ll find that the CN community will provide incredible support ... so read and ask questions !



#6 SamplingNature

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Posted 15 August 2019 - 07:05 PM

Thanks for all of the input. So, Sharpcap allows near-realtime viewing of stacked images?

#7 RazvanUnderStars

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Posted 15 August 2019 - 08:23 PM

Yes (you see the stack being built in real time) plus A LOT more. It can help with or even automate precise focusing. It can do plate solving (=figure out what part of the sky you're seeing) and point the scope to the object you wanted, even if not in the image because the goto was off. You can do a precise polar alignment in minutes. It can do some live-postprocessing of the stacked images. And much, much more. See https://docs.sharpcap.co.uk/3.2/ for what it can do. It's probably too much to read everything, but just a peek at the table of contents will tell you what it can do. It's an amazing piece of software.

 

Much like others above, I don't recommend the Nexstar 6 unless you're on a budget. The mount is not that great, mechanically speaking. I had one. A more modern mount like Evolution with much better mechanics and features (built-in battery, WiFi you can control from tablet or computer) will help a lot. Better skip buying an expensive Pelican case and invest in the actual mount & scope & camera (I drive 100km to a dark site with the scope on very large pillows). Also, an 8" scope will bring you roughly 1.75x more light than a 6" one so if you can, buy an 8" one. BTW, Celestron has a sale now, I think they have one every August and at other times, but I'm not really tracking them. 

 

Also, I don't recommend R2. It's old, limited and inflexible compared to the CMOS cameras now (ZWO gives you a lot more choices, see https://agenaastro.c...rs-guide.html).

 

Also, if you have a Go-To mount, I don't understand why you'd need a Telrad. I know there are people who love to star hop but that requires good skies and time. Lots of time. Nothing wrong with it, but if you're time is limited, do you want to spend time searching for an object or observing it? A Go-To mount will bring you to the object and combined with SharpCap's plate solving, the object will be in the centre of the image, all within a minute of so.

 

Finally, I'd suggest to not buy everything at once. Pick either visual or EAA and learn the practice. There's enough to learn in each direction. You also have the risk of buying something now only to find out a few months later, with more knowledge acquired in the meantime, that you should have bought something else. Depending on where you live, it may be easy or hard to sell equipment in case you want something else. Take that into account. So if you're planning to get the ETX-80, stick with it for a while. Learn what it can do, what it cannot and after a while you'll know better what else you'll want (because it's an 80mm refractor, most targets will be really small).

 

I'd also suggest to go through the CN forums (welcome, by the way) to learn about more equipment choices. If you have one around, join an astronomy club to see other scopes or go to a star party where you'd see dozens or hundreds .

 

 

Thanks for all of the input. So, Sharpcap allows near-realtime viewing of stacked images?


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#8 OleCuss

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Posted 15 August 2019 - 08:36 PM

Thanks for all of the input. So, Sharpcap allows near-realtime viewing of stacked images?

I like to emphasize that nothing we do is truly real-time.  When that is not clear we have people trying to engage in things like occultation timing with unsuitable calibration and bad results.  We may do some stuff which is near-real-time, but not real-time.

 

There was a time when we were using analog CCD cameras without digital signal processing and the images were so close to real time as to make no difference.   Even if you get a new analog CCD camera it will be very unlikely to give you truly real-time images because they do too much processing of the signal to avoid delays.

 

But SharpCap is the most talked-about software used for what I call OAP (Observational AP) and just about everyone else calls EAA.  It is really quite sophisticated software which will do star registration and stacking along with some pretty good processing for surprisingly good results.

 

However, the OAP world is somewhat divided and this can end up dictating either your choice of camera or your choice of software.

 

SharpCap is set up for native support of the cameras sold by a number of manufacturers such as ZWO, QHY, and Altair.  (There are others which you can look up on their site.)  Native support means you have relatively direct and full access to effectively all of the features of the SharpCap software.

 

If you get a camera which is not natively supported by SharpCap but there are ASCOM drivers for your camera, you will likely still be able to use SharpCap but there will be some features you will not be able to access (and may not miss).

 

There are several other sets of software which are pretty well liked by some/many and provide at least the basic functions.

 

ToupTek makes cameras sold by a number of re-sellers and value-added resellers.  They do not have native SharpCap support but instead have included ToupTek software whose name will usually end with the "Sky".  You cannot use this software with anything but a ToupTek-derived camera.

 

Atik has their "Infinity" software.  As far as I can tell this is also pretty good software which is very user-friendly.  I tend to see the images as over-processed but they are admittedly pretty good and some folk want to use nothing else.  The software was first developed for their "Infinity" camera and it appears to have kept the name even though they've altered it to run on other cameras they make.  You cannot use the Infinity software on anything but an Atik camera.

 

Starlight Live is devoted to use with Starlight Xpress cameras.  Some like that software enough that they'll buy only Starlight Xpress cameras so that they can use that software.

 

There may be some other options as well.  Well, OK, one would be the Stellina software but you cannot use that with anything but the Stellina.

 

But I think that SharpCap may be the most sophisticated software currently available for use with our cameras.




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