smokin oakum
Pooh-Bah
Reged: 09/24/07
Posts: 1426
Loc: Wilmington, NC
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What kind of barlows are you guys using with you cameras? I know most of the time, it's not needed, but say on M57, would you use a 2" barlow or a 1 1/4" barlow. How much mag can this thing stand as well? To me my money has just been switched to buying barlows, instead of eyepieces.
Neil
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Broadcasting live views of the night sky @
Sparkcast
C11 CGE / Hyperstar
MallinCam Hyper Plus Color
Orion 12" XTi f/4.9
MoonLite Focuser
Round Table Platform
12" Parralax rings
Cape Fear Astronomy Club
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midway199
super member
Reged: 04/21/04
Posts: 108
Loc: Illinois
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I'm wondering if doubling your focal length wouldn't be more detrimental for DSO's. You'd have to increase your exposure time. I'll have to give it a shot one night. I have however, used my StellaCam 3 with 2x and 2.5x Powermates for planetary work. It does exposures at a fraction of a second as well. The change in image scale, is very much like putting in a higher magnification eyepiece.
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Matthew Sherman
StellaCam 3
Celestron NexStar 11 @ f/3.3
Starmaster 12.5"
Starmaster 18"
Tom Osypowski Equatorial Platform
Butterfield East Video Observatory
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smokin oakum
Pooh-Bah
Reged: 09/24/07
Posts: 1426
Loc: Wilmington, NC
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Good point, but couldn't you use a focal reducer to offset it?
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Broadcasting live views of the night sky @
Sparkcast
C11 CGE / Hyperstar
MallinCam Hyper Plus Color
Orion 12" XTi f/4.9
MoonLite Focuser
Round Table Platform
12" Parralax rings
Cape Fear Astronomy Club
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midway199
super member
Reged: 04/21/04
Posts: 108
Loc: Illinois
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That would be like multiplying by two and then dividing by two. You're essentially back where you started with a lot more glass in the path!
I hope I'm answering your question right.
Using a barlow effectively increases your focal length - resulting in longer exposures, where focal reducers do just the opposite. Sorry if I'm telling you something you already know!
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Matthew Sherman
StellaCam 3
Celestron NexStar 11 @ f/3.3
Starmaster 12.5"
Starmaster 18"
Tom Osypowski Equatorial Platform
Butterfield East Video Observatory
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smokin oakum
Pooh-Bah
Reged: 09/24/07
Posts: 1426
Loc: Wilmington, NC
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That does make sence.  Well at least my scope starts out at f/4.9, so a 2X barlow would be f/9.8, so that wouln't be that bad for say 56s exposers.
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Broadcasting live views of the night sky @
Sparkcast
C11 CGE / Hyperstar
MallinCam Hyper Plus Color
Orion 12" XTi f/4.9
MoonLite Focuser
Round Table Platform
12" Parralax rings
Cape Fear Astronomy Club
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rolandlinda3
Carpal Tunnel
Reged: 01/24/06
Posts: 1616
Loc: Crozet VA 22932
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See my thread (Astrovideo is great but keep critical EPs) and you will find comments about my use of a 2 in Televue Barlow, which I highly recommend when you need optical magnification on small objects or details of a larger one. The link is below. Roland
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/2047414/page/0/view/collapsed/sb/5/o/all/fpart/1#Post2047448
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smokin oakum
Pooh-Bah
Reged: 09/24/07
Posts: 1426
Loc: Wilmington, NC
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Thanks for the link Roland. Great write up too. I guess for my 12" scope something like the TeleVue 2x BIG Barlow 2 Inch with 1-1/4 Adapter would be ideal, right?
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Broadcasting live views of the night sky @
Sparkcast
C11 CGE / Hyperstar
MallinCam Hyper Plus Color
Orion 12" XTi f/4.9
MoonLite Focuser
Round Table Platform
12" Parralax rings
Cape Fear Astronomy Club
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rolandlinda3
Carpal Tunnel
Reged: 01/24/06
Posts: 1616
Loc: Crozet VA 22932
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I believe so. The current TV barlows are made a bit better in terms of coatings also. Funny that it is not a highly talked about solution, but their Barlow is very nice. Being 2 inch, it gives you plenty of flexibility for other uses also. Roland
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smokin oakum
Pooh-Bah
Reged: 09/24/07
Posts: 1426
Loc: Wilmington, NC
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Thanks buddy!
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Broadcasting live views of the night sky @
Sparkcast
C11 CGE / Hyperstar
MallinCam Hyper Plus Color
Orion 12" XTi f/4.9
MoonLite Focuser
Round Table Platform
12" Parralax rings
Cape Fear Astronomy Club
|
Bowmoreman
Carpal Tunnel
Reged: 09/11/06
Posts: 2992
Loc: Bolton, MA
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Quote:
I believe so. The current TV barlows are made a bit better in terms of coatings also. Funny that it is not a highly talked about solution, but their Barlow is very nice. Being 2 inch, it gives you plenty of flexibility for other uses also. Roland
Hey Roland, what about the Televue 2x PowerMate instead of the 2" big barlow? any thoughts there... any tradeoffs I should know about?
Thanks
clear skies
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Dave
Ustream
YLive
XT10i, RTP, CGE, R200CF, TMB80SS
31T5, 22T4, 13Ethos, 8Ethos, TV 3-6 Zoom; Paracorr
MallincamColorHyperPlus,SBIG STV&237A;CanonRebel Xti
WilderSkiesObservatory(BYO #90)
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smokin oakum
Pooh-Bah
Reged: 09/24/07
Posts: 1426
Loc: Wilmington, NC
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Good question Dave. I just asumed that the big barlow was a better choice since it was made for newtronians. What do I know though. I haven't even gotten my camera yet.
Neil
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Broadcasting live views of the night sky @
Sparkcast
C11 CGE / Hyperstar
MallinCam Hyper Plus Color
Orion 12" XTi f/4.9
MoonLite Focuser
Round Table Platform
12" Parralax rings
Cape Fear Astronomy Club
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Douglas
Vendor - Night Vision Astronomy
Reged: 05/21/07
Posts: 291
Loc: Pound Ridge, NY
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I used the Televue 2x Powermate with the MallinCam on Mars but it didn't work out as well as I had hoped. I think it was just too much power. Then I tried the zoom feature in the MallinCam menu and it worked out pretty good. I haven't tried any barlows.
- Doug
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Night Vision Astronomy
BIPH - Binocular Photon Machine
IDA Member
Obsession 12.5" Argo Navis/ServoCat #1528
Tak FSQ-106 EDX2 & EM-200 Temma II
Canon 450 Xsi No Modification
QSI 532ws CCD with AstroDon Filters
Home Built Gen III Image Intensifier
Denk II Binos D14s & D21s
MallinCam Hyper Plus Color
Bunch of Naglers & 13mm Ethos
Stellarvue 80mm F/7 NHNG #36
PST SolarMax 40 Double Stack
Canon 15 x 50 IS Binoculars
AstroTrac
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Gord
sage
Reged: 01/06/04
Posts: 497
Loc: Toronto, ON, Canada
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I've used various different barlows and PowerMates with my MallinCam over the years for looking at different objects. So far, I've done:
-Focal reducer
-No focal reducer
-2x Antares Elite barlow
-2x Celestron EP kit barlow
-2.5x PowerMate
-5x PowerMate
-Antares and Celestron barlows stacked
-5x PowerMate and Antares stacked
-5x and 2.5x PowerMates stacked
They all work to varying degree's of success depending on the object, the scope, and of course the conditions. For deep sky (and recording as faint as possible), the using the focal reducer and a fast scope is the best, no questions. But, that being said some DSO's work good with longer FL's. Namely brighter ones.
Globular clusters (or at least the Messier ones) I find to be too bright with even my MallinCam II color and the focal reducer in my 10". They are all burned out. And you need to keep in mind how much less sensitive this camera is compared to the new ones. It's quite a bit less sensitive than even my Pro B&W (these are all from the 2 sec integration days...), and nothing like the new ones.
On objects like these, I find it best to haul the FL out quite a bit. A 2x barlow or even the 2.5 PowerMate works great. Gives a nice closeup of all the stars in the center of the cluster.
I even find objects like M57 or M1 work pretty well without the reducer or with a barlow. Less brightness, but a much bigger image.
Of course on planets, or splitting doubles, I like to really stretch things out! If you haven't tried splitting doubles with these cameras, give it a try. It's a lot of fun and again a different way to look at things. Really neat to show people in a group.
Anyways, all I can really say is just play with it and have fun. Try different things. See what you come up with. That's just the way Rock does things. That's how he was able to get images of DSO's during the daytime using his camera. Just playing around!
Have fun,
-Gord
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* Celestron C10/Normand Fullum primary
* Tasco 11TR/Normand Fullum primary
* Orion StarBlast
* Orion Apex 102
* SkyWatcher 80ED
* Celestron CG5a mount
* MallinCam Pro & Color II
* Lots of other astro toys
...and the best wife I could ever dream of for letting it all happen! 
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