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Photo Forum / Digital Photography / DSLR Cameras / February 2006Shooting through a telescope - need advice
My neighbor just gave me a Meade ETX 90 telescope, and I just purchased a T adaptor for it and a T-Mount for my D70. The book says to put the telescope in polar mode and use the motor, which I understand, but anybody have any other tips for shooting through a telescope? I don't have a mirror lockup, but I do have the infrared remote. The T adaptor attaches directly to the back of the scope, so I'm using the scope as the lens. Also, anybody have any experience with those solar filters? Do they really work? (Thought I'd ask before going blind.) TIA Sheldon >My neighbor just gave me a Meade ETX 90 telescope, and I just purchased a T >adaptor for it and a T-Mount for my D70. The book says to put the telescope >in polar mode and use the motor, which I understand, but anybody have any >other tips for shooting through a telescope? I don't have a mirror lockup, >but I do have the infrared remote. The T adaptor attaches directly to the >back of the scope, so I'm using the scope as the lens. What do you plan to shoot? The sky or terrestrial? >Also, anybody have any experience with those solar filters? Do they really >work? (Thought I'd ask before going blind.) > >TIA > >Sheldon >>My neighbor just gave me a Meade ETX 90 telescope, and I just purchased a >>T [quoted text clipped - 7 lines] > > What do you plan to shoot? The sky or terrestrial? At this point I'm thinking mostly sky. >>>My neighbor just gave me a Meade ETX 90 telescope, and I just purchased a >>>T [quoted text clipped - 9 lines] >> >At this point I'm thinking mostly sky. I have a similar scope I use for terrestrial... I found it too hard to focus for night use, plus I don't have a motor mount so it limits me to moon shots! The best solar filter is made by Baader Planetarium and sold by Astro Physics. They do work. ONLY use real solar filters, not mylar "emergency" blankets sold in sporting goods stores or other things like that. Thousand Oaks Optical make glass solar filters. If you shoot terrestrial subjects, you don't run the telescope motor. If you shoot the Moon, Sun, you need to run the drive. Shooting planets requires an "eyepiece projection adapter" and IMO, is a waste of time with the C90 owing to the very small aperture, but you can give it a shot. Deepsky objects are not good targets. It's difficult to track well with the basic ETX drive (depends also on the model of ETX) and the slow focal ratio (f13.5 or so) makes it a bit slow for deepsky pictures. If you do decide to shoot the planets, opening the shutter of the camera and using a black card over the front of the scope, not touching the scope and simply flashing the card out of the way to achieve exposure is one way to isolate the scope from vibrations that could ruin the shot. > The best solar filter is made by Baader Planetarium and sold by Astro > Physics. [quoted text clipped - 16 lines] > exposure is one way to > isolate the scope from vibrations that could ruin the shot. Good idea to kill vibrations. >My neighbor just gave me a Meade ETX 90 telescope, and I just purchased a T >adaptor for it and a T-Mount for my D70. The book says to put the telescope >in polar mode and use the motor, which I understand, but anybody have any >other tips for shooting through a telescope? The number one hardest thing to get right is focus. The viewfinders are never bright enough to get a decent focus on anything but planets and you can get an accurate focus on almost nothing. But with patience and some trials you can get some nice shots. For planets and the moon you don't even need the scope in polar mode. Exposures less than a couple minutes won't show any skew in alt-az mode. At ISO 400, planets and the moon will require exposures of 1/60th to about 5 seconds. Forget about camera metering. > I don't have a mirror lockup, >but I do have the infrared remote. Mirror lockup isn't really needed, but you absolutely cannot be touching any part of the scope or camera. Even heavy walking can cause noticible shake. > The T adaptor attaches directly to the >back of the scope, so I'm using the scope as the lens. > >Also, anybody have any experience with those solar filters? Do they really >work? (Thought I'd ask before going blind.) A good filter that attaches to the front of the scope will work fine. There are many to choose from and the differences for a small scope are not that large. Most solar photography will be affected far more by atmospheric effects than by the filter.  SignatureRay Fischer rfischer@sonic.net >>My neighbor just gave me a Meade ETX 90 telescope, and I just purchased a >>T [quoted text clipped - 33 lines] > are not that large. Most solar photography will be affected far more > by atmospheric effects than by the filter. I'm at 8000', so I shouldn't have too much of a problem. >>The number one hardest thing to get right is focus. The viewfinders >>are never bright enough to get a decent focus on anything but planets >>and you can get an accurate focus on almost nothing. But with patience >>and some trials you can get some nice shots. I'll second that. You can get DSLRfocus, a free program that will read out the camera onto a laptop, for example. You then manual focus. It's a slow but necessary step. >>For planets and the moon you don't even need the scope in polar mode. >>Exposures less than a couple minutes won't show any skew in alt-az >>mode. You do need to track for any exposure longer than about 1/15 second when using any telescope, or the image will be trailed. >>>Also, anybody have any experience with those solar filters? Do they >>>really [quoted text clipped - 4 lines] >>are not that large. Most solar photography will be affected far more >>by atmospheric effects than by the filter. I have an Orion StarMax solar filter, http://www.telescope.com/jump.jsp?itemType=PRODUCT&itemID=189 it works well: http://www.clarkvision.com/galleries/gallery.astrophoto-1/web/sun.c11.19.2003.v1 .4-800b.html > I'm at 8000', so I shouldn't have too much of a problem. Hmmm. You in the western US? I'm in Colorado. A few other points: Tracking is the limiting factor, so for stars you need to do multiple short exposures and add/average them together. E.g: http://www.clarkvision.com/galleries/gallery.astrophoto-1/web/m31.c07.10.2005.Av g23-75s-v1.6-700.html You can use a free program like Registax or one with more capability like ImagesPlus. You need to take your images in raw mode in order to do averaging, and convert the raw data to linear output (Photoshop will not do that). You might sign up for the Yahoo group digital_astro where you can read/et lots of advice, and see much better pictures than mine. I suggest first trying the moon, then if you want stars and nebulae, try the Great Orion nebula (the middle star in Orion's sword) (44 1-minute exposures): http://www.clarkvision.com/galleries/gallery.astrophoto-1/web/m42-700mm_crw_8588 -8631.44min.16b.try3.v12-800.html Try 15-second exposures at ISO 800 on Orion, then if you get round stars, up the exposure time. If you do 20 to 100 15-second exposures and stack them, you can get some beautiful pictures. After you do the Orion Nebula, everything else (nebulae and galaxies) are much fainter and harder. Star clusters should be pretty easy, but usually do not show much color. Roger I'm up in Aspen. Lots of laws regarding light pollution so the sky looks pretty good here. >>>The number one hardest thing to get right is focus. The viewfinders >>>are never bright enough to get a decent focus on anything but planets [quoted text clipped - 61 lines] > > Roger >I'm up in Aspen. Lots of laws regarding light pollution so the sky looks >pretty good here. 90% of all light pollution could be STOPPED in cities if they would just GET RID of those 1950s style street lights that blast light out too far sideways and upward. The kinds of fully shielded lights they have near small airports would be a GREAT idea. Additionally, they waste less power and don't blind you while you drive your car when it rains. Other stupid forms of light wastage could be legislated against, like leaving tennis court floodlights on until 3:00 in the morning and STUPID auto dealers who leave 6000 bare bulbs burning all night. It kills me that city officials are always after the "public" to cut energy use and they permit this kind of thing to go on with businesses and government. -Rich > It kills me that city officials are always after the > "public" to cut energy use and they permit this kind of thing to go on > with businesses and government. What are you, some kind of commie? Individuals, businesses, churches, and the government should be able to wreak havoc on the environment in any way they please!!! Greg >> It kills me that city officials are always after the >> "public" to cut energy use and they permit this kind of thing to go on [quoted text clipped - 5 lines] > >Greg It's purely capitalistic to advocate cities clamping down on energy waste because it's tax payer money they are burning up. -Rich >>> It kills me that city officials are always after the >>>"public" to cut energy use and they permit this kind of thing to go on [quoted text clipped - 8 lines] > It's purely capitalistic to advocate cities clamping down on energy > waste because it's tax payer money they are burning up. As long as you don't tell my business what to do that's fine with me. Otherwise I'm going to LIGHT THAT SKY UP LIKE IT'S DAYLIGHT 25 HOURS A DAY!!!! You're such a hypocrite. You're only for government regulation when it fits your needs, just like all right wingers. Greg Signature"All my time I spent in heaven Revelries of dance and wine Waking to the sound of laughter Up I'd rise and kiss the sky" - The Mekons >>>> It kills me that city officials are always after the >>>>"public" to cut energy use and they permit this kind of thing to go on [quoted text clipped - 17 lines] > >Greg I'm for regulation when it makes sense. Like to corral leftwingers into pens. -Rich > "G.T." <getnews1@dslextreme.com> >>> It's purely capitalistic to advocate cities clamping down on energy >>> waste because it's tax payer money they are burning up. [quoted text clipped - 8 lines] >I'm for regulation when it makes sense. Like to corral leftwingers >into pens. ^^^^ They're called "concentration camps", fascist. SignatureRay Fischer rfischer@sonic.net >>>> It kills me that city officials are always after the >>>>"public" to cut energy use and they permit this kind of thing to go on [quoted text clipped - 19 lines] > > Greg Well, all I know is that your lights cannot light anything but your own property, which puts a damper on some security lights. But, it beats having to have a fight with your neighbor when all you have to do is call the cops to enforce the law. Also, all city lights are directed downward toward the street and the sidewalk. To be quite honest, a few mercury vapor lights around here would make the intersections a lot safer, but the tradeoff is a beautiful night sky. >"Ray Fischer" <rfischer@sonic.net> wrote in message >>>My neighbor just gave me a Meade ETX 90 telescope, and I just purchased a >>>T [quoted text clipped - 35 lines] > >I'm at 8000', so I shouldn't have too much of a problem. It's _always_ a problem during the day. Being up that high helps a lot, but any breeze will cause image shimmer. SignatureRay Fischer rfischer@sonic.net |
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