Minor Planet Ceres


jimcoble2000
 

Just got a look at Ceres tonight. It is easy to locate in the constellation Taurus slightly above the apex star in the "V" of Taurus. It is just above Gamma Taurus. At magnitude 7.2 it is an easy telescopic object. Tonight is the night before it's opposition and that makes it the brightest it gets. This is due to the very rough texture of the surface. When viewed from an angle it's brightness is lowered due to the combination of high bright surfaces and long shadows. At opposition, the light is very high so the shadows are well illuminated along with the high spots adding to the total brightness. This is the same reason that the moon jumps up exponentially in brightness just as it approaches full moon. On the moon it is the micro rough regolith surfaces which cause this effect.

Ceres was once considered a planet and it certainly does lie in the plane of the ecliptic, so well delineated this year by Jupiter, Venus, and Saturn. Nice target for the next few nights.


Ian Stewart
 

Will take a look later tonight. Have a great Thanksgiving ... Cheers Ian

On 11/24/2021 8:26 PM, jimcoble2000 via groups.io wrote:
Just got a look at Ceres tonight. It is easy to locate in the constellation Taurus slightly above the apex star in the "V" of Taurus. It is just above Gamma Taurus. At magnitude 7.2 it is an easy telescopic object. Tonight is the night before it's opposition and that makes it the brightest it gets. This is due to the very rough texture of the surface. When viewed from an angle it's brightness is lowered due to the combination of high bright surfaces and long shadows. At opposition, the light is very high so the shadows are well illuminated along with the high spots adding to the total brightness. This is the same reason that the moon jumps up exponentially in brightness just as it approaches full moon. On the moon it is the micro rough regolith surfaces which cause this effect.

Ceres was once considered a planet and it certainly does lie in the plane of the ecliptic, so well delineated this year by Jupiter, Venus, and Saturn. Nice target for the next few nights.


Kent Blackwell
 

One of my logs using the 10" Orion IntelliScope (at NW River Park in 2013) noted a yellow tint, yet a more recent log (2018) with my 4" Takahashi noted a blue tint. What color did you see?


Ian Stewart
 

More of an orange tint last night in my 5 inch triplet. M38 and M36 in Auriga were gorgeous last night as well.

On 11/25/2021 7:44 AM, Kent Blackwell wrote:
One of my logs using the 10" Orion IntelliScope (at NW River Park in 2013) noted a yellow tint, yet a more recent log (2018) with my 4" Takahashi noted a blue tint. What color did you see?


jimcoble2000
 

Yes exactly the color that I saw. Oddly, Ceres is one of the darkest objects around. Albedo ranges from 0 which is total non reflectance to 1 which is a theoretical 100% reflectance. Snow is around 0.9. Charcoal comes in at 0.04 Ceres come in a a whopping non starter of 0.07 .

Glad you wrote this as that was my impression too. Supposed to rain tonight so may be tough to see how far it has changed position since last night. Friday should be ok.

On Thursday, November 25, 2021, 08:36:26 AM EST, Ian Stewart <ian@...> wrote:


More of an orange tint last night in my 5 inch triplet. M38 and M36 in Auriga were gorgeous last night as well.

On 11/25/2021 7:44 AM, Kent Blackwell wrote:
One of my logs using the 10" Orion IntelliScope (at NW River Park in 2013) noted a yellow tint, yet a more recent log (2018) with my 4" Takahashi noted a blue tint. What color did you see?


jimcoble2000
 

Hey Kent. Do you have a date on that 2013 observation or the 2018?

On Thursday, November 25, 2021, 07:44:21 AM EST, Kent Blackwell <kent@...> wrote:


One of my logs using the 10" Orion IntelliScope (at NW River Park in 2013) noted a yellow tint, yet a more recent log (2018) with my 4" Takahashi noted a blue tint. What color did you see?


jimcoble2000
 

I ran the visual magnitudes for a few oppositions from 2020 to2023. The magnitudes change a bit as, I assume, we encounter it at varying distances during our respective orbits. It also rotates quite quickly at 9 hours and that may change it's appearance or perceived color within one night. We are in a 1:4.6 resonance orbit so we will come into opposition at differing distances each year. That is most likely for the different appearances reported. I plan to take a look Friday and Saturday to see if the appearance changes.

On Thursday, November 25, 2021, 08:36:26 AM EST, Ian Stewart <ian@...> wrote:


More of an orange tint last night in my 5 inch triplet. M38 and M36 in Auriga were gorgeous last night as well.

On 11/25/2021 7:44 AM, Kent Blackwell wrote:
One of my logs using the 10" Orion IntelliScope (at NW River Park in 2013) noted a yellow tint, yet a more recent log (2018) with my 4" Takahashi noted a blue tint. What color did you see?