David's Astronomy Pages CCD Images - Session 907 (2021-08-23)

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Objects	Session Notes
15P/Finlay - Comet 17P/Holmes - Comet C/2019 U6 (Lemmon) - Comet (attempt)     Nova Cas 2021 - Nova (V1405 Cas)     NGC 6184 - Spiral Galaxy with Type Ia Supernova 2021wkv     Variable Stars (photometric monitoring) - SS Cyg, BL Lac - RX And attempt failed due to cloud     Nearby Stars (astrometric monitoring) - None	- Night Session (2.8 hours). - Session interrupted by cloud / Session finished early due to cloud - Main aims of the session were to acquire a selection of targets as conditions allowed - 12" LX200 + ST-10XME for imaging - TS 80mm APO + ZWO ASI178MC for guiding & imaging - Ambient Temperature: 10.5°C (min) - CCD Temperature:  -5°/-10°C - Notes from 2021-08-23 >>    [ Local Files >> ]   -

15P/Finlay - Comet

15P/Finlay (passing through Gemini) Sun Distance 1.16 AU Earth Distance 1.39 AU (207.9 million km) Comet position is shown by white cross-hairs Comet is fainter than it's expected mag (+13.4)		15P/Finlay - 2021-08-24, Detail Autoguided on offset star using PHD2 with Lock Shift set at the comet's rate of motion (Ra 125.73 arcsec/hr, Dec 7.58 arcsec/hr) Comet (very faint) shown by white cross-hairs
Annotated CCD Image (50% size, square root scale) 3 x 60s exposure (average combine), 3x3 binning, C Filter 2021-08-24 02:06 UT (#907071-73) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2		Annotated CCD Image (100% size, square root scale, cropped) Image details as left
Images of 15P/Finlay on Comets 2021 Page >>

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17P/Holmes - Comet

17P/Holmes - 2021-08-24 (passing through Auriga) Sun Distance 2.50 AU Earth Distance 2.60 AU (389.4 million km) Comet position is shown by white cross-hairs Note : Comet's current sun distance  (2.50 AU) is very similar to the distance it had when it erupted in 2007 (2.54 AU)		17P/Holmes - 2021-08-24, Detail Autoguided on offset star using PHD2 with Lock Shift set at the comet's rate of motion (Ra 61.30 arcsec/hr, Dec 17.49 arcsec/hr) Comet (very faint) shown by white cross-hairs Comet is just visible and seems close to it's expected mag (+18.0)
Annotated CCD Image (50% size, square root scale) 3 x 60s exposure (average combine), 3x3 binning, C Filter 2021-08-24 00:33 UT (#907035-37) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2		Annotated CCD Image (100% size, square root scale, cropped) 6 x 60s exposure (average combine), 3x3 binning, C Filter 2021-08-24 00:34 UT (#907035-41) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2
Images of 15P/Holmes on Comets 2021 Page >>
Earlier images of 15P/Holmes on Comets 2007 Page >>

Earlier explosive eruption of Comet 17P/Holmes in 2007 Frames taken 2007-10-25 to 2007-10-30 showing rapidly expanding coma  2007-10-25 (2.1 arc min diam)  2007-10-29 (7.0 arc min diam) 2007-10-30 (9.3 arc min diam) Sun Distance 2.54 AU, Earth Distance ?

Animated CCD Images 5 x 10s exposure (average combine), 2x2 binning, C Filter,  Log Scale Frame 1 : 2007-10-25 20:45h UT (#227055-59) Frame 2 : 2007-10-29 04:43h UT (#228038-42) Frame 3 : 2007-10-30 04:47h UT (#229035-39)

Earlier montage of images of Comet 17P/Holmes from 2007 (2007-10-25 to 2007-11-16)

CCD Image Montage (30% size) Images from 2007-10-25 to 2007-11-16 2x2 binning, various exposures [Larger Image,  50% size]

More images of 15P/Holmes Explosive Eruption on Comets 2007 Page >>

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C/2019 U6 (Lemmon) - Comet (Attempted Sighting)

C/2019 U6 (Lemmon) (passing through Cepheus) Sun Distance 5.50 AU  (receeding) Earth Distance 5.08 AU (760.1 million km) No indication of cometary object at expected position (circled) With hindsight detection of C/2019 U6 (Lemmon) at this distance was always going to fail.  Comet has now been removed from active observing list.		C/2019 U6 (Lemmon) - 2021-08-23, Detail Autoguided on offset star using PHD2 with Lock Shift set at the comet's rate of motion (Ra -34.60 arcsec/hr, Dec -11.36 arcsec/hr) No indication of cometary object at expected position (circled) All the objects in view are present in DSS & PanStarrs images in Aladdin. Expected comet mag (+20.9) is far fainter than limiting mag (+18.5 to +19.1)
Annotated CCD Image (50% size, square root scale) 3 x 60s exposure (average combine), 3x3 binning, C Filter 2021-08-23 23:39 UT (#907005-07) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2		Annotated CCD Image (125% size, square root scale, cropped) 6 x 60s exposure (average combine), 3x3 binning, C Filter 2021-08-23 23:41 UT (#907005-10) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2
Images of C/2019 U6 (Lemmon) on Comets 2020 Page >>

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Nova Cas 2021 - Nova (V1405 Cas)

Nova Cas 2021 (Cassiopeia) Nova in Cassiopeia discovered 2021-03-18.4236,  by Yuji Nakamura (Japan) Magnitude at discovery +9.6 (unfiltered CCD) AT2021hkn (Type: Nova) reported by 2021/03/30.055 UT by Gaia Alias: Gaia21bpe, AT2021hkn, V1405 Cas

Nova Cas 2021 / AT2021hkn - 2021-08-24 (T+158.6d) Image below (2021-08-24.038) was taken 158.6 days after discovery of Nova Nova is shown by white cross hairs.  Measured magnitude +8.01 Note: star object is saturated and shows some blooming, mag is probably underestimated (linked with Detection Threshold = 50)

CCD Image (100% size, linear scale, cropped) 5 x 30s exposure (average combine), 3x3 binning, C Filter 2021-08-24 00:57 UT (#907051-55) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

Nova Cas 2021 (V1405 Cas) Spectra - 2021-08-24 (T+158.6d)

Spectra produced in AstroMain using Image taken with Star Analyser 200 2 x 30s exposure (average combine), 2x2 binning, S Filter 2021-08-24 00:59 UT (#907056-57) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

Images of Nova Cas 2021 on Novae Page >>

Nova Cas 2021 (V1405 Cas) Spectra - 2021-08-24 (T+147.0d) Taken with Star Analyser 200 (slitless diffraction grating, 200 lines/mm)

CCD Image (48% size, linear scale) 2 x 30s exposure (average combine), 2x2 binning, S Filter 2021-08-24 00:59 UT (#907056-57) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

Nova Cas 2021 (V1405 Cas) Spectra compared with HIP 115566 /  SAO 20610 (Spectra Type B9III) NB.  Total length of spectra is spread over 250 pixels (2x2 binning) and corresponds to 25.5 Angstrom/Pixel (This is with an image collected using 2x2 binning. For an image with 1x1 binning the spectra would have been spread over 500 pixels. The RSpec guide is a spectra spread of 225 to 400 pixels)

CCD Image (100% size, square root scale, cropped) Image details as above

HIP 115566 / SAO 20610 Spectra (Type B9III)

CCD Image (100% size, square root scale, cropped) Image details as above

Nova Cas 2021 (V1405 Cas) Spectra Showing Strong H-alpha emission line, with weaker H-beta and He-I (D3) lines

CCD Image (100% size, square root scale, cropped) Image details as above

Nova Cas 2021 (V1405 Cas) Spectra - Calibrated .  Calibrated using two point calibration in RSpec 2.0.0 1) Zero Order Star at 0 and 2) Ha emission line at 6563 A.  Giving calibration scale of 25.5 Angstroms/pixel

Spectra produced in RSpec 2.0.0 using Image taken with Star Analyser 200 5 x 30s exposure (average combine), 3x3 binning, C Filter 2021-08-24 00:57 UT (#907051-55) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

Nova Cas 2021 (V1405 Cas) Spectra - Corrected .  Calibrated Spectra corrected using Instrument Response determined from Reference Star HIP 115566 / SAO 20610 (Type B9III) taken at same time & at same altitude (85 deg) as Nova Cas 2021 V1405 is reported to have a Classical Nova Spectrum cf. V1405 Spectrum by Raymond Kneip, 2021-03-19

Spectra produced in RSpec 2.0.0 using Image taken with Star Analyser 200 Image details as above

HIP 115566 / SAO 20610 (Type B9III) Spectra - Raw (Red) vs Corrected (Blue)

Spectra produced in RSpec 2.0.0 using Image taken with Star Analyser 200 Image details as above

Instrument Response determined from HIP 115566 / SAO 20610 Spectra and Smoothed B9iii Reference Spectra Altitude 85.0 deg

Instrumental Response determined in RSpec 2.0.0 using Image taken with Star Analyser 200 Image details as above

Nova Cas 2021 (V1405 Cas) Spectra (Red) compared with HIP 115566 / SAO 20610 Spectra (Blue) Both spectra calibrated and corrected

Spectra produced in RSpec 2.0.0 using Image taken with Star Analyser 200 Image details as above

Images of Nova Cas 2021 on Novae Page >>

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NGC 6184 - Spiral Galaxy with Type Ia Supernova 2021wkv

NGC 6184 with SN 2021wkv (Hercules) SN 2021wkv (Type: Ia, zhost=0.027329) discovered 2021/08/20.277 UT by ATLAS Alias: ATLAS21bgqy.  Magnitude +18.2 at discovery  (Rochester Supernova site )

NGC 6184 with SN 2021wkv (T+3.7d)

Annotated CCD Image  (50% size, square root scale) 2 x 180s exposure (average combine), 3x3 binning, C Filter 2021-08-24 00:15 UT (#907026-29) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

NGC 6184 with SN 2021wkv - 2021-08-24 (T+3.7d) Image below (2021-08-24.003) was taken 3.7 days after discovery of 2021wkv SN position is shown by white cross-hairs. Measured mag +16.3

Annotated CCD Image  (125% size, square root scale, cropped) 2 x 180s exposure (average combine), 3x3 binning, C Filter 2021-08-24 00:15 UT (#907026-29) 12" LX200R (at f/10.4) + ST-10XME Auto-guided using TS 80mm APO, ZWO ASI178MC & PHD2

Images of SN 2021wkv (NGC 6184) on Supernovae 2021 Page >>

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