Re: [tec-scopes] Re: I Tried Something a Bit Different...


Jul 31, 2013

 


----------------------------

#24156 Jul 31, 2013

Hello Group,



I thought I'd post a photo of something I tried that is perhaps a bit unusual. I have used my TEC140 (on PMX) together with an Astro Physics 2X barlow, and guided through an ONAG (St-i). This is from the fairly light polluted Sydney suburb of North Curl Curl so I also used a Hutec IDAS. The result is certainly not perfect. I had difficulties guiding that remain unresolved. It may be the IR light through the ONAG, or an issue with my PMX, or some stupidity on my part! Some of the star distortion may also be due to the barlow. However, I do think I was able to pull out some pleasing detail. The image is the result of 4 months of experimentation. The color data was particularly difficult to collect. Some is 1x1 and some is 2x2. Each color was around 2 hours or so, and the luminance is 4 hours. Camera is a Moravian G2-8300. Image scale was .575 or 1940mm focal length.



www.pbase.com/prejto/image/151597292



Here is a photo of the setup. The barlow had to be placed after the ONAG, and the IDAS filter cannot go in front of the ONAG either as it will block IR. Not an ideal setup, but it was a fun experiment. I think I will not continue down this path. I need more aperture, or a camera with higher QE. Maybe a TEC180 would solve my problem...



www.pbase.com/prejto/image/151028536



Thanks for looking.

Peter



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#24157 Jul 31, 2013

Very nice result, Peter.  I know how difficult color is to do well in a light-polluted environment!  I ended up doing mostly narrowband from Boston.

...no...aperture fever never ends g>.

   Cheers...Neil

 www.flemingastrophotography.com Direct from Boston - brilliant diamonds in pea soupAlso check out the astro_narrowband Yahoo group!

From: prejto peter.rejto@...> To: tec-scopes@yahoogroups.com Sent: Wednesday, July 31, 2013 9:56 PM Subject: [tec-scopes] I Tried Something a Bit Different...

 Hello Group,



I thought I'd post a photo of something I tried that is perhaps a bit unusual. I have used my TEC140 (on PMX) together with an Astro Physics 2X barlow, and guided through an ONAG (St-i). This is from the fairly light polluted Sydney suburb of North Curl Curl so I also used a Hutec IDAS. The result is certainly not perfect. I had difficulties guiding that remain unresolved. It may be the IR light through the ONAG, or an issue with my PMX, or some stupidity on my part! Some of the star distortion may also be due to the barlow. However, I do think I was able to pull out some pleasing detail. The image is the result of 4 months of experimentation. The color data was particularly difficult to collect. Some is 1x1 and some is 2x2. Each color was around 2 hours or so, and the luminance is 4 hours. Camera is a Moravian G2-8300. Image scale was .575 or 1940mm focal length.



www.pbase.com/prejto/image/151597292



Here is a photo of the setup. The barlow had to be placed after the ONAG, and the IDAS filter cannot go in front of the ONAG either as it will block IR. Not an ideal setup, but it was a fun experiment. I think I will not continue down this path. I need more aperture, or a camera with higher QE. Maybe a TEC180 would solve my problem...



www.pbase.com/prejto/image/151028536



Thanks for looking.

Peter



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#24178 Aug 2, 2013

Hi Peter,

I'd *love* to take a look at the picture but it says it can't be found! Please post it again as I also run a TEC140 on a PMX and am having also guiding issues, so I'd like to share ideas with you -but first take a loo at the picture itself.

You also seem to have the feathertouch motor, as I do. Is this the older one or the new one sold by Starizone (I guess)?

I'm also having issues with that so I'd like to hear from you...

Best regards,

Ferran.



--- In tec-scopes@yahoogroups.com, "prejto" peter.rejto@...> wrote:

>

> Hello Group,

>

> I thought I'd post a photo of something I tried that is perhaps a bit unusual. I have used my TEC140 (on PMX) together with an Astro Physics 2X barlow, and guided through an ONAG (St-i). This is from the fairly light polluted Sydney suburb of North Curl Curl so I also used a Hutec IDAS. The result is certainly not perfect. I had difficulties guiding that remain unresolved. It may be the IR light through the ONAG, or an issue with my PMX, or some stupidity on my part! Some of the star distortion may also be due to the barlow. However, I do think I was able to pull out some pleasing detail. The image is the result of 4 months of experimentation. The color data was particularly difficult to collect. Some is 1x1 and some is 2x2. Each color was around 2 hours or so, and the luminance is 4 hours. Camera is a Moravian G2-8300. Image scale was .575 or 1940mm focal length.

>

> www.pbase.com/prejto/image/151597292

>

> Here is a photo of the setup. The barlow had to be placed after the ONAG, and the IDAS filter cannot go in front of the ONAG either as it will block IR. Not an ideal setup, but it was a fun experiment. I think I will not continue down this path. I need more aperture, or a camera with higher QE. Maybe a TEC180 would solve my problem...

>

> www.pbase.com/prejto/image/151028536

>

> Thanks for looking.

> Peter

>



----------------------------

#24181 Aug 3, 2013

If you are having guiding issues, did you verify the periodic error and if its out of spec. You must correctly apply PEC. The MX has a 229 sec period and the slope of the PE is roughly double that of AP's. The velocity off sidereal rate is calculated by slope of an averaged PE curve. You can easily calculate this using Excel. You can even superimpose a sinusoidal curve over the data and use simple calculus/physics to find the max velocity and acceleration off sidereal rate. I say all this since my MX had this issue, and had to prove to SB that my RA worm was out of spec. FYI you can also calculate PE by measuring worm mesh runout but you'll require a high precision dial indicator.

Sent from Yahoo! Mail for iPhone





From:

ferranmazzanti Ferran.Mazzanti@...>;

To:

tec-scopes@yahoogroups.com>;

Subject:

[tec-scopes] Re: I Tried Something a Bit Different...

Sent:

Sat, Aug 3, 2013 2:47:37 AM



Hi Peter,I'd *love* to take a look at the picture but it says it can't be found! Please post it again as I also run a TEC140 on a PMX and am having also guiding issues, so I'd like to share ideas with you -but first take a loo at the picture itself.You also seem to have the feathertouch motor, as I do. Is this the older one or the new one sold by Starizone (I guess)?I'm also having issues with that so I'd like to hear from you...Best regards,Ferran.

--- In tec-scopes@yahoogroups.com, "prejto" peter.rejto@...> wrote:>> Hello Group,> > I thought I'd post a photo of something I tried that is perhaps a bit unusual. I have used my TEC140 (on PMX) together with an Astro Physics 2X barlow, and guidedthrough an ONAG (St-i). This is from the fairly light polluted Sydney suburb of North Curl Curl so I also used a Hutec IDAS. The result is certainly not perfect. I had difficulties guiding that remain unresolved. It may be the IR light through the ONAG, or an issue with my PMX, or some stupidity on my part! Some of the star distortion may also be due to the barlow. However, I do think I was able to pull out some pleasing detail. The image is the result of 4 months of experimentation. The color data was particularly difficult to collect. Some is 1x1 and some is 2x2. Each color was around 2 hours or so, and the luminance is 4 hours. Camera is a Moravian G2-8300. Image scale was .575 or 1940mm focal length.> > www.pbase.com/prejto/image/151597292> > Here is a photo of the setup. The barlow had to be placed after the ONAG, and the IDAS filter cannotgo in front of the ONAG either as it will block IR. Not an ideal setup, but it was a fun experiment. I think I will not continue down this path. I need more aperture, or a camera with higher QE. Maybe a TEC180 would solve my problem...> > www.pbase.com/prejto/image/151028536 > > Thanks for looking.> Peter>



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----------------------------

#24183 Aug 4, 2013

--- In tec-scopes@yahoogroups.com, Tim Khan timkhan@...> wrote: >

> If you are having guiding issues, did you verify the periodic error and if its out of spec. You must correctly apply PEC. The MX has a 229 sec period and the slope of the PE is roughly double that of AP's. The velocity off sidereal rate is calculated by slope of an averaged PE curve. You can easily calculate this using Excel. You can even superimpose a sinusoidal curve over the data and use simple calculus/physics to find the max velocity and acceleration off sidereal rate. I say all this since my MX had this issue, and had to prove to SB that my RA worm was out of spec. FYI you can also calculate PE by measuring worm mesh runout but you'll require a high precision dial indicator.br /br /Sent from Yahoo! Mail for iPhone

>

Hi Tim,

Thanks for your message. Yes, PEC is applied, and applied correctly via PemPro. My uncorrected PE is about 2.3 arcsec peak to peak, and corrected below1 arcsec. My problem is that I'll be guiding just fine and then RA will give a sudden jump of more than 1 pixel, then it will be fine until another large jump. I did need to change my original black belts for grey belts and there was some contamination which I took great care to remove. I wonder, though, if some might have found its way to the worm? Could that cause this? I've adjusted the cam stop but it has not improved. For others with a similar issue it seems to improve via a cam adjustment. I'm not really sure if my mount ever was without this problem. At f7 it didn't cause too much of an issue and everything was so new to me I wrote it all off as me just knowing what I was doing. Now, at f14 this is a much bigger issue and I'm feeling more confident about what should and shouldn't be. I should post at SB and see what comes. Peter



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#24184 Aug 4, 2013

the periodicity of the "jump" is important evidence. track an equatorial star so you get the fastest rate in the drive mechanism. and while this isn't an SB forum, please report back on your experience with tech support at SB. good luck!

--- In tec-scopes@yahoogroups.com, "prejto" peter.rejto@...> wrote:

> Thanks for your message. Yes, PEC is applied, and applied correctly via PemPro. My uncorrected PE is about 2.3 arcsec peak to peak, and corrected below1 arcsec. My problem is that I'll be guiding just fine and then RA will give a sudden jump of more than 1 pixel, then it will be fine until another large jump. I did need to change my original black belts for grey belts and there was some contamination which I took great care to remove. I wonder, though, if some might have found its way to the worm? Could that cause this? I've adjusted the cam stop but it has not improved. For others with a similar issue it seems to improve via a cam adjustment. I'm not really sure if my mount ever was without this problem. At f7 it didn't cause too much of an issue and everything was so new to me I wrote it all off as me just knowing what I was doing. Now, at f14 this is a much bigger issue and I'm feeling more confident about what should and shouldn't be. I should post at SB and see what comes.



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#24188 Aug 5, 2013

I'll contact you privately since this is off topic.

From: prejto peter.rejto@...> To: tec-scopes@yahoogroups.com Sent: Sunday, August 4, 2013 10:00 AM Subject: [tec-scopes] Re: I Tried Something a Bit Different...



--- In tec-scopes@yahoogroups.com, TimKhan timkhan@...> wrote: >> If you are having guiding issues, did you verify the periodic error and if its out of spec. You must correctly apply PEC. The MX has a 229 sec period and the slope of the PE is roughly double  that of AP's. The velocity off sidereal rate is calculated by slope of an averaged PE curve. You can easily calculate this using Excel. You can even superimpose a sinusoidal curve over the data and use simple calculus/physics to find the max velocity and acceleration off sidereal rate. I say all this since my MX had this issue, and had to prove to SB that my RA worm was out of spec. FYI you can also calculate PE by measuring worm mesh runout but you'll require a high precision dial indicator.br /br /Sent from Yahoo! Mail for iPhone> Hi Tim,Thanks for your message. Yes, PEC is applied, and applied correctly via PemPro. Myuncorrected PE is about 2.3 arcsec peak to peak, and corrected below1 arcsec. My problem is that I'll be guiding just fine and then RA will give a sudden jump of more than 1 pixel, then it will be fine until another large jump. I did need to change my original black belts for grey belts and there was some contamination which I took great care to remove. I wonder, though, if some might have found its way to the worm? Could that cause this? I've adjusted the cam stop but it has not improved. For others with a similar issue it seems to improve via a cam adjustment. I'm not really sure if my mount ever was without this problem. At f7 it didn't cause too much of an issue and everything was so new to me I wrote it all off as me just knowing what I was doing. Now, at f14 this is a much bigger issue and I'm feeling more confident about what should and shouldn't be. I should post at SB and see what comes. Peter



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