Firstly, plz forget about the joke thread I made, about the snot nebula; I didn't want that to cause me to be forgotten and/or ignored on Astrobin; I'm not always a careless troll like that, and it wasn't my intention to piss off people; I was thinking that I was funny. Also know that I'm most likely one of the youngest Astrophotographers on all of Astrobin, so a crazy thing like that was expected to come at some point. Wont happen anymore.
I bought a "4tronix" secondary mirror heater, and I just tested it, it heats, and it also fits my secondary, however, I heard from another thread that secondary mirrors increased star size, and generally degraded image quality, and that a dew shield is a better option.
So my question is, should I still use it on my secondary, or should I use it to warm up my ASIair instead? because my ASIair also gets dewy, and I'm afraid the water can get inside and short something.
I got the heater because my backyard gets very humid at night, I think because I'm about 30 miles close to the ocean, and sometimes it's a little windy, and I'm thinking that windiness can carry the moisture onto my secondary.
I know already that my dew situation is so bad that even a 5.5 inch dew shield didn't stop dew from getting on a surface (my guidescope, which I'm not using anymore), from my location, and I heard 5.5 inches should've stopped dew formation.
I don't even have a dew shield for my Newtonian anyways.
I'm also afraid of fog, because summer is gonna be worse in humidity; last night I saw that the sky was clear, but then it got really foggy, and that's probably just the beginning; is there some accurate online fog/humidity forecast website?
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Kudos to you for recognizing a mistake, that takes courage. How old are you?
Infrared satellite images (sat24) are useful to spot short-term fog.
A dew heater could distort the wavefront, but if it can save an otherwise unusable night, that's for the better!
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Spacetime Pictures:
Kudos to you for recognizing a mistake, that takes courage. How old are you?
Infrared satellite images (sat24) are useful to spot short-term fog.
A dew heater could distort the wavefront, but if it can save an otherwise unusable night, that's for the better!
I'm 16. Started photography at about 13, and then went to astro once I took a picture of my first DSO, when I was about 14.
So far, I haven't had any secondary mirror dew problems; the heater was just precautionary.
Maybe I should use it for the ASIair, then if dew gets on my secondary, I get a dew shield?
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The Asiair heats by itself, I would not worry about it.
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You are going to need a dew heater and a dew shield. Pulse the heater on low. The thermal expansion and heat plumes from the heater can create issues.
Also i doubt anyone cares about the “snot nebula”? Own it. Run with it. Dont apologize. Dont do things you think you’ll later regret.
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Some 5mm EVA foam makes good and easy DIY dew shields. I've found that applying about 2 or 3 watts of heat to the body of my focuser prevents dew on the coma corrector and the secondary mirror. I used to have severe dew issues even with a dew shield. I did use secondary heaters of about 0.5 watts but I didn't like running wires across the spider as it altered the normally very clean diffraction spikes.
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I'll throw this one in for your weather question. Astropheric is one great app to use for our hobby. There are others like Clear Outside or even Clear Sky Chart. As far as fog goes you need to know the temperature and dew point at your site. When they get within 5 degrees F of each other the chance for fog is high. The closer they are to each other, the higher the chance for fog. You should be able to get that info from a quick internet search of your local weather or from an environmental sensor on your rig such as focuser sensor, dew heater controller, or something like a Pegasus Power Box sensor. Many of them report both temperature and dew point. There are several other factors needed for fog to actually form so local weather stations/forecasts are usually the best resource.
CS,
Jeff
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If the tube is well insulated by the dew shield with reflective layer outside then you shan't have many problems with dew (I never had any on either the 6" or the 12") even without a secondary heater (which are very no-no in my book). Best to use thick comping mats for this. It needs to run from the focuser out to 1.5x the aperture diameter from the tube end.
And if is foggy you just pack up and go.
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Spacetime Pictures:
The Asiair heats by itself, I would not worry about it.
Thanks, didn't know.
Wes Schwarz:
You are going to need a dew heater and a dew shield. Pulse the heater on low. The thermal expansion and heat plumes from the heater can create issues.
Also i doubt anyone cares about the “snot nebula”? Own it. Run with it. Dont apologize. Dont do things you think you’ll later regret.
I just got a Dew Ninja dew heater (strip) for the telescope tube; where should I place it? The back of the scope, the mid, or the front?
Thanks for the advice.
Mike Hamende:
Some 5mm EVA foam makes good and easy DIY dew shields. I've found that applying about 2 or 3 watts of heat to the body of my focuser prevents dew on the coma corrector and the secondary mirror. I used to have severe dew issues even with a dew shield. I did use secondary heaters of about 0.5 watts but I didn't like running wires across the spider as it altered the normally very clean diffraction spikes.
Good idea about the foam.
I wont use the secondary heater; I've been really wanting clean diffraction spikes.
About the focuser: how did you apply heat the focuser? A low profile one like this? https://www.teleskop-express.de/en/telescope-accessories-5/focusers-adapters-motorfocus-296/focusers-and-micro-transmission-92/ts-optics-2-low-profile-rack-and-pinion-newtonian-focuser-8-kg-payload-974
I don't see any place to put a dew heater on there...
Jeff Reitzel:
I'll throw this one in for your weather question. Astropheric is one great app to use for our hobby. There are others like Clear Outside or even Clear Sky Chart. As far as fog goes you need to know the temperature and dew point at your site. When they get within 5 degrees F of each other the chance for fog is high. The closer they are to each other, the higher the chance for fog. You should be able to get that info from a quick internet search of your local weather or from an environmental sensor on your rig such as focuser sensor, dew heater controller, or something like a Pegasus Power Box sensor. Many of them report both temperature and dew point. There are several other factors needed for fog to actually form so local weather stations/forecasts are usually the best resource.
CS,
Jeff
Thanks a lot for the info! Didn't know about Astrosperic.
andrea tasselli:
If the tube is well insulated by the dew shield with reflective layer outside then you shan't have many problems with dew (I never had any on either the 6" or the 12") even without a secondary heater (which are very no-no in my book). Best to use thick comping mats for this. It needs to run from the focuser out to 1.5x the aperture diameter from the tube end.
And if is foggy you just pack up and go.
I think I'll use foam, thank you for all the info.
----------------------------
And what do I do with my secondary heater? Maybe put it somewhere on the mount? Close to the RA/DEC motors maybe?
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This is unrelated, but I'm making my dark and bias frame library right now.
Can someone tell me how many is a good amount?
So far I took:
200 Bias for -10C, 100 Gain
100 Darks for 10s, -10C, 100 Gain
100 Darks for 60s, -10C, 100 Gain
30 Darks for 300s, -10C, 100 Gain
I'm thinking waiting for 100 darks for 300s is way too long; Is 40-50 good enough?
I understand darks and bias are not really important for a 533 camera, but I'm thinking that darks/bias must benefit it in some way; I'm still waiting for more parts to be delivered (like the TS-optics focuser), so that I can do normal imaging, so I'm taking this opportunity to take calibration frames.
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I've used reflectix around my tubes for a few years with wrap around dew heaters under them near the front. I've tried many a secondary heater and they all led to affecting the stability of the mirror. Primary dew heaters, the same. I've had a lot of dew otherwise with the heat bands turned off. I frequently have 90% humidity. My Pegasus astro box controls the temps automatically based on humidity.
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This is unrelated, but I'm making my dark and bias frame library right now.
Can someone tell me how many is a good amount?
So far I took:
200 Bias for -10C, 100 Gain
100 Darks for 10s, -10C, 100 Gain
100 Darks for 60s, -10C, 100 Gain
30 Darks for 300s, -10C, 100 Gain
I'm thinking waiting for 100 darks for 300s is way too long; Is 40-50 good enough?
I understand darks and bias are not really important for a 533 camera, but I'm thinking that darks/bias must benefit it in some way; I'm still waiting for more parts to be delivered (like the TS-optics focuser), so that I can do normal imaging, so I'm taking this opportunity to take calibration frames.
See John Hayes' post in this thread. Something like 16 darks is all you need.
https://www.astrobin.com/forum/c/astrophotography/deep-sky/lets-discuss-about-dark-bias-dark-flats/?page=1 |
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Arun H:
This is unrelated, but I'm making my dark and bias frame library right now.
Can someone tell me how many is a good amount?
So far I took:
200 Bias for -10C, 100 Gain
100 Darks for 10s, -10C, 100 Gain
100 Darks for 60s, -10C, 100 Gain
30 Darks for 300s, -10C, 100 Gain
I'm thinking waiting for 100 darks for 300s is way too long; Is 40-50 good enough?
I understand darks and bias are not really important for a 533 camera, but I'm thinking that darks/bias must benefit it in some way; I'm still waiting for more parts to be delivered (like the TS-optics focuser), so that I can do normal imaging, so I'm taking this opportunity to take calibration frames.
See John Hayes' post in this thread. Something like 16 darks is all you need.
https://www.astrobin.com/forum/c/astrophotography/deep-sky/lets-discuss-about-dark-bias-dark-flats/?page=1
Oh, I remember that rule now.
But what happens when I go past 16, with bias and darks?
If that was talked about in the linked thread, I didn't understand it.
And BTW, I did take at least thirty 300s dark frames, but I found, near the end of my darks Autorun session, that the cooler was using %100 power on my ASIair, and was actually not cooling to -10C; it was more like -8C, and my 533 was hot when I touched it; is everything okay with my 533? I didn't expect the hotness.
And are all my darks okay to use together? It's only a difference of -2C between my first 300s darks and last 300s darks...
If I'm not very clear about something, plz let me know.
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Mike Hamende:
Some 5mm EVA foam makes good and easy DIY dew shields. I've found that applying about 2 or 3 watts of heat to the body of my focuser prevents dew on the coma corrector and the secondary mirror. I used to have severe dew issues even with a dew shield. I did use secondary heaters of about 0.5 watts but I didn't like running wires across the spider as it altered the normally very clean diffraction spikes.
Good idea about the foam.
I wont use the secondary heater; I've been really wanting clean diffraction spikes.
About the focuser: how did you apply heat the focuser? A low profile one like this? https://www.teleskop-express.de/en/telescope-accessories-5/focusers-adapters-motorfocus-296/focusers-and-micro-transmission-92/ts-optics-2-low-profile-rack-and-pinion-newtonian-focuser-8-kg-payload-974
I don't see any place to put a dew heater on there...
I use adhesive backed polymide film heaters like this. If you have a dew controller with RCA outputs you can use a pigtail like this.
If you don't have a dew heater controller you can you a PWM controller like this with pigtails like these to adjust the power of the film heater.
As far as where to put the heater, just stick it anywhere on the fixed cylindrical barrel of the focuser. If you are not electrically inclined then tread carefully.
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Mike Hamende:
Mike Hamende:
Some 5mm EVA foam makes good and easy DIY dew shields. I've found that applying about 2 or 3 watts of heat to the body of my focuser prevents dew on the coma corrector and the secondary mirror. I used to have severe dew issues even with a dew shield. I did use secondary heaters of about 0.5 watts but I didn't like running wires across the spider as it altered the normally very clean diffraction spikes.
Good idea about the foam.
I wont use the secondary heater; I've been really wanting clean diffraction spikes.
About the focuser: how did you apply heat the focuser? A low profile one like this? https://www.teleskop-express.de/en/telescope-accessories-5/focusers-adapters-motorfocus-296/focusers-and-micro-transmission-92/ts-optics-2-low-profile-rack-and-pinion-newtonian-focuser-8-kg-payload-974
I don't see any place to put a dew heater on there...
I use adhesive backed polymide film heaters like this. If you have a dew controller with RCA outputs you can use a pigtail like this.
If you don't have a dew heater controller you can you a PWM controller like this with pigtails like these to adjust the power of the film heater.
As far as where to put the heater, just stick it anywhere on the fixed cylindrical barrel of the focuser. If you are not electrically inclined then tread carefully.
Thanks for the advice
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Arun H:
This is unrelated, but I'm making my dark and bias frame library right now.
Can someone tell me how many is a good amount?
So far I took:
200 Bias for -10C, 100 Gain
100 Darks for 10s, -10C, 100 Gain
100 Darks for 60s, -10C, 100 Gain
30 Darks for 300s, -10C, 100 Gain
I'm thinking waiting for 100 darks for 300s is way too long; Is 40-50 good enough?
I understand darks and bias are not really important for a 533 camera, but I'm thinking that darks/bias must benefit it in some way; I'm still waiting for more parts to be delivered (like the TS-optics focuser), so that I can do normal imaging, so I'm taking this opportunity to take calibration frames.
See John Hayes' post in this thread. Something like 16 darks is all you need.
https://www.astrobin.com/forum/c/astrophotography/deep-sky/lets-discuss-about-dark-bias-dark-flats/?page=1
Oh, I remember that rule now.
But what happens when I go past 16, with bias and darks?
If that was talked about in the linked thread, I didn't understand it.
And BTW, I did take at least thirty 300s dark frames, but I found, near the end of my darks Autorun session, that the cooler was using %100 power on my ASIair, and was actually not cooling to -10C; it was more like -8C, and my 533 was hot when I touched it; is everything okay with my 533? I didn't expect the hotness.
And are all my darks okay to use together? It's only a difference of -2C between my first 300s darks and last 300s darks...
If I'm not very clear about something, plz let me know.
nothing prevents you from getting more. There is no downside other than time. A two degree difference is not material. Remember your lights will not be at the exact temperature either.
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4.02
4.07
0.90
1.43
1.51
7.76
6.06
11.95
