I tried... C/2017 T1 (Heinze) did not work out...

[calli]

Hi there.

after C/2015 V2 Johnson https://photos.app.goo.gl/yIbgsliYNY047pOl2

and P41/Tuttle-Giacobini-Kresak https://photos.app.goo.gl/FwBAZD4z0cE15dMn2

last year I though I try on C/2017 T1 Heinze. I was hoping for my first comet with a tail. I must say that I am using a Nikon D5100 with a Vivitar S1 3.5@210mm on a NexStar SLT Goto Mount. I am living in Berlin, close to the airport Schönefeld, so high light pollution (not to curse about the neighbors who seem to fear darkness so much that they plastered thier houses with LED lamps). So I used a rough alignment on Deneb, beause it was already below 0°C yesterday 18:00 local time. Then I slewed to Heinze with Stellariums help and got the right direction I guess (FOW is 6x4° with the said setup). I used then Astrotortilla to check and re-slew my (wacky) mount to exact the given position. Then I started to do 20s exposures at 800ISO which already gave me red skies and I though a good compromise of tracking and light.

I was expecting at least a fuzzy spot but nothing. Rechecked the coordinates with calsky.org and today with theskylive.com

It should have been there I guess. But I cant exclude some stupid errors from me. I used also DSS Live Stacker to get a better idea how it would turn out, and also after stacking I got nothing.

Maybe it is one of the star-like pixels in center but how do I check? Stellarium does not show enough stars, I tried DS9 but this crashes so often on me. Maybe I can load some star chart/image and compare it with my astrometry.net solved FITS with embedded coordinates?

Maybe I also could not get enough light, or the comet is to small for my apreture? May I was hoping too much after the tellings about the magnitude?

Cheers,

Carsten

[MikeODay]

Forgive the obvious question but are you sure the comet is in the frame?

nova.astrometry.net reports the following for your image:

Which is in the region of where the comet was at 1800hrs on the 14th but it was moving resonably fast.

What was the exact time and date of your session?

[calli]

January 14, from 18:50 to 19:50 local time (UTC +1)

I checked in Stellarium and in that time the comet was very well centered into the quite big FOV (6x4° as you did see also in the astrometry data).

I also re-centered one time approx in the middle of the session to the calculated coordinates.

I was some time thinking that I entered wrong location coordinates to my mount or Stellarium, but of course we can check this with astrometry.net and the image is also by eye to be located in the right spot.

So... clueless still. Maybe it is to faint still for my technic and gear or someting other.

Carsten

[MikeODay]

So I agree with you, it should be there ...

In this region of your image 

Is this a single frame or stacked image?  

[calli]

It is a stack. Maybe not the best idea for a fast Comet. And yes thats the Region i looked for it. I suspect one "star" to be the comet but cant prove. 

 

Carsten

[goodricke1]

I have failed to spot this comet in an 8-inch scope, although 13th mag stars were visible in the field. It is very diffuse and the generous quoted estimates, which refer to its total surface brightness, don't reflect how difficult it is to spot visually. I'm not going to waste any more time trying to track it down.

[MikeODay]

4 hours ago, calli said:

It is a stack. Maybe not the best idea for a fast Comet. And yes thats the Region i looked for it. I suspect one "star" to be the comet but cant prove. 

 

Carsten

I don't know what software you used to stack, and again forgive the question, but are you sure that you did not remove the comet by sigma clipping ( or similar ) ?  Over the one hour time frame the comet would have moved a fair way and should appear as a short line in your stacked image ( unless the stacking software removed it as unwanted signal due to its non-stationary nature ).

Can you post a 100% crop of the relevant area from a single frame?

[MikeODay]

The following image indicate approx. how far the comet would have moved during your session:

 

[calli]

Sigma... That rings some bells... :-)

EDIT: I used "Median".

I try again... I remember to think about options but may have been distracted by tiredness or so.

Carsten

[calli]

Here are three subs, start middle and end of session. They are in Nikon NEF raw format.

https://www.dropbox.com/s/v9sxvl4n13b4uo6/Heinze.7z?dl=0

Carsten

[MikeODay]

Hey, Carsten

I will take a look at them and see what I can find ...

Cheers

Mike

[calli]

Much apreciated, but don't put too much time in that bad data.

Carsten

[Guy Wells]

The comet is not in your image, although your pointing is fine.

[calli]

Just now, Guy Wells said:

The comet is not in your image, although your pointing is fine.

Strange! But thanks for all your efforts guys!

So who took it? :-) Maybe it just evaporated... Haha.

Carsten

[Guy Wells]

In a single sub the faintest stars around mag +11.

[calli]

1 hour ago, Guy Wells said:

In a single sub the faintest stars around mag +11.

Yea, in the stack it is more like +13 or so. I so far only have Stellarium and I still wonder how I could get most easy better data from the region. I cant find some stars in Stallarium I can easy see on my stacked image. Like the atached.

Carsten

[MikeODay]

20 hours ago, calli said:

Yea, in the stack it is more like +13 or so. I so far only have Stellarium and I still wonder how I could get most easy better data from the region. I cant find some stars in Stallarium I can easy see on my stacked image. Like the atached.

Carsten

I believe the star you have indicated is the one tagged in the SkySafari image below

 

What was the start time of the 13 shot sequence?  

[calli]

1 hour ago, MikeODay said:

I believe the star you have indicated is the one tagged in the SkySafari image below

 

 

 

What was the start time of the 13 shot sequence?  

Yes that fits. I just installed kStars I think this have a more complete star data base. EDIT: too bad that kstars does not find heinze ;-(

My session was from 18:51 to 19:50 86 subs for good. EDIT: The 3 shots were from start middle and end of my complete sequence.

Carsten

[Guy Wells]

This is the exact position of the comet, marked with the square, at the time you tried to image it.

[calli]

Ok, so I have learned not to give too much to all the news "bino-comet" and mag xx etc. :-)

Thanks for all your efforts! Much apreciated. I learned a lot.

Carsten

[Guy Wells]

You're welcome.